Eucalyptus leaves; the oil is steam-distilled from fresh leaves or branch tips.

Essential Oils & Aromatherapy · Essential oil

Eucalyptus Oil

Q: Is eucalyptus oil safe to swallow?

No. We do not advise swallowing it. A Melbourne series found 59% of 109 young children who swallowed it had symptoms, from drowsiness to unconsciousness, adults have had seizures after swallowing it, and one man died. If a child or pet may have swallowed any essential oil, call poison control (US: 1-800-222-1222) or your emergency number and do not make them vomit.

Q: Can eucalyptus oil cause seizures?

Yes, there are many reports. A pooled review of 110 cases (49 children) found seizures after skin use, breathing the vapour and swallowing, with inhaling the commonest route. Most people recovered. The EU says the oil must not be used by children with a history of seizures.

Q: Is eucalyptus oil safe for babies and children?

The EU says not under 24 months, because it can cause a reflex spasm of the voice box. Never put the oil or a rub on or near the face of a baby or small child. Ask a paediatric clinician before using it on any child, and keep bottles out of reach.

Q: Is eucalyptus oil safe for cats and dogs?

No. The ASPCA lists eucalyptus as toxic to dogs, cats and horses, with drooling, vomiting, diarrhea, depression and weakness. We found no study of diffused oil in pets, so keep oils, rubs and diffusers away from animals and ask a vet.

Q: Can eucalyptus oil trigger asthma?

It can irritate the airways in some people. One woman had vocal cord tightening, which can look like asthma, when she breathed eucalyptus. We found no study measuring asthma attacks with the oil. Do not use it in place of prescribed asthma medicine, and stop if breathing gets worse.

Q: Does eucalyptus oil help a cold, sinus infection or cough?

The EU accepts it for cough with a cold on long use, but no trial of the oil itself was found. The positive trials are of cineole capsules, a medicine, for sinus infection, bronchitis, asthma and COPD, mostly from one research group.

Q: What is the difference between eucalyptus oil and cineole capsules?

Cineole is the main compound in the oil. The capsules hold only cineole and are made as a medicine; most of the good trials used them. The bottled oil holds other compounds and is dangerous if swallowed. Results for the capsule do not carry over to the oil.

Q: Is eucalyptus oil safe in pregnancy or breastfeeding?

The EU says safety has not been established and does not recommend it. Cineole crossed the placenta in rats and was found in breast milk in some women who took it by mouth. Ask your midwife or doctor.

Q: Does eucalyptus oil interact with medicines?

The EU reports none, but animal work suggests cineole may speed up liver enzymes, and one man on warfarin had a fall in his clotting test while using a lozenge with eucalyptus oil, menthol and liquorice. Tell your pharmacist if you use it regularly, especially with warfarin or seizure medicines.

Q: Can eucalyptus oil cause an allergic reaction?

Yes. The EU lists allergic reactions, including severe ones, and contact eczema, with unknown frequency. Its safety database includes an anaphylactic reaction in a child using a bath additive. Stop and wash the oil off if a rash appears.

Eucalyptus globulus Labill. and E. radiata A.Cunn. ex DC. · also called Blue gum oil, eucalyptus essential oil, narrow-leaved peppermint oil (E. radiata), cineole-rich oil

Eucalyptus oil is the strong, cooling oil steam-distilled from the leaves of eucalyptus trees. It is used in vaporisers, chest rubs, cold remedies and aromatherapy, and its main compound is 1,8-cineole. The best studies for colds, sinus infections and lung disease tested cineole capsules, a medicine, not the oil. The main caution: never swallow the oil, because a small amount can cause drowsiness and seizures in a child.

General information, not medical advice. Last substantive update October 25, 2026 · Not medically reviewed. A named clinician has not signed off on this page. How this page is made

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About Eucalyptus Oil

Eucalyptus oil is a strong-smelling oil from the leaves of eucalyptus trees, best known in chest rubs and vaporisers. Safety comes first: swallowing it has caused seizures and coma, mostly in children, and it must never go on or near a baby's face. Most of the good research is on cineole, its main compound, taken as a capsule medicine for colds, sinus infections, asthma and COPD. For the oil itself there is mostly tradition, plus small trials of breathing it for pain.

What eucalyptus oil is

Eucalyptus oil is the essential oil obtained by passing steam through the fresh leaves or branch tips of eucalyptus trees rich in 1,8-cineole, mainly Eucalyptus globulus. The EU monograph also names E. polybractea and E. smithii. E. radiata, the narrow-leaved peppermint, is a separate accepted species also sold as eucalyptus oil. GBIF lists both as accepted species in the myrtle family.

The oil is mostly 1,8-cineole, also called eucalyptol. One commercial E. globulus oil measured 63.1% cineole, with p-cymene, alpha-pinene and limonene next; the pharmacopoeia standard quoted in the EU report asks for at least 70%. Products sold as eucalyptus oil in India have been found to contain camphor, which adds seizure risk.

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What people use it for, and how strong the evidence is

For cough with a cold and for muscle pain, the EU accepts the oil on long use alone. The EU assessment report found no clinical study of the oil itself.

The better trials test isolated 1,8-cineole capsules, a medicine. Two German trials found acute sinus infections eased faster than with placebo or another herbal product, and a 2023 review rated cineole among the best herbal options with moderate certainty. One trial each in acute bronchitis, asthma and COPD found gains, but they come from one research group and the COPD and bronchitis trials were paid for by the maker.

For the oil itself, two small trials of breathing it found lower pain scores after knee surgery and in rheumatoid arthritis. The smell is hard to hide, so these results may be inflated.

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The research in one view

Most trials are short, small and from one research group, and several were paid for by the maker of a cineole capsule. A 2022 review of eucalyptus cough products called the effect minimal and of uncertain importance. Lab and animal work suggests cineole calms inflammation signals and blocks a pain-sensing nerve channel, but that has not been shown to help people.

No study of eucalyptus oil in a diffuser, and none of the oil for sleep, mood or memory, was found.

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Oil, capsule, rub and mouth products are different things

Results for cineole capsules do not show that the oil works. A capsule made as a medicine is not the same as swallowing oil from a bottle, which is dangerous. Chest rubs and lozenges are mixtures with menthol, camphor or other oils, and one man on warfarin had a drop in his clotting test while using a lozenge with eucalyptus oil, menthol and liquorice, so eucalyptus cannot be blamed alone.

Lemon eucalyptus (Corymbia citriodora) is a different plant, used as an insect repellent.

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What regulators say

The EU herbal committee's monograph (adopted November 2024) accepts eucalyptus oil medicines for cough with a cold and localised muscle pain, on the basis of long-standing use. It lists as contraindicated: allergy to the oil or cineole, children with a history of seizures, and children under 24 months. Use in pregnancy and breastfeeding is not recommended, and it reports no known interactions.

Poison Control says swallowed eucalyptus oil can cause seizures and that essential oils are potent and should be locked away from children and pets.

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At a glance

Traditional uses history, not proof

Inhaled, rubbed on the skin or added to baths for cough with a cold (accepted by the EU herbal committee on long-standing use).
Rubbed on the skin or added to baths for localised muscle pain (EU, traditional use).
Added to vaporisers, chest rubs and lozenges for a cooling, clearing scent.

Studied for research

Cough with a cold, oil, traditional use, insufficient
Acute sinus infection, cineole capsules (a medicine), moderate
Acute bronchitis, cineole capsules, low
Asthma, cineole capsules, low
COPD flare-ups, cineole capsules, low
Pain after surgery or in arthritis, inhaled oil, low
Gum inflammation, extract in chewing gum, low

Main compounds

1,8-Cineole (eucalyptol), the main component, at least 70% by the pharmacopoeia standard
Alpha-pinene, limonene and p-cymene, minor components
Camphor, not a normal component; its presence suggests a fake or adulterated oil

Common forms

Essential oil (steam-distilled leaves or branch tips)
Isolated cineole capsules (a medicine, tested in the trials)
Chest rubs, vaporiser liquids and lozenges (mixtures with menthol, camphor or other oils)
Licensed inhaled, skin and bath medicines in the EU (a different product from a bottle of oil)

Research links: EMA: Eucalyptus oil herbal summary · Poison Control: Essential oils · ASPCA: Eucalyptus · Cineole in COPD: placebo-controlled trial (abstract) · Eucalyptus oil seizures: pooled case review (abstract) · Research Library · Genes & Biomarkers Library

What it is and its history

Accepted scientific name: Eucalyptus globulus Labill. (and Eucalyptus radiata A.Cunn. ex DC.)
Naming authority: Labill. (Jacques-Julien Houtou de Labillardiere)
Synonyms: Eucalyptus gigantea Denham (listed as a synonym in GBIF); Eucalyptus globulus var. bicostata Maiden (GBIF synonym)
Common names: Tasmanian blue gum, southern blue gum, blue gum, bluegum eucalyptus (English); Eucalipto blanco (Spanish); Eucalyptus commun, gommier bleu (French); Blauer Eukalyptus, Blaugummibaum, Fieberbaum (German); Narrow-leaved peppermint (Eucalyptus radiata) (English)
Family or group: Myrtaceae
Classification: Plantae > Tracheophyta > Magnoliopsida > Myrtales > Myrtaceae > Eucalyptus > Eucalyptus globulus
Native range: Native to south-eastern Australia and Tasmania (EU reports); cultivated in the Mediterranean, North Africa, the Caucasus, Florida, California, Brazil, Mexico, Jamaica and India.
Habitat: Tall evergreen trees grown in plantations; the oil is steam-distilled from the leaves.
What it looks like: Part used: Fresh leaves or branch tips are steam-distilled to make the oil (EU report). This page does not describe how to recognise the trees.
Cultivation: Grown commercially in many warm regions for pulp and oil (EU report). Cultivation details were not checked beyond that.
Harvest and processing: The essential oil is steam-distilled and rectified from fresh leaves or branch tips (European Pharmacopoeia definition quoted by the EU report).
Look-alikes and adulterants: Name: Eucalyptus radiata and other cineole-rich species sold as 'eucalyptus oil'; Note: The EU oil monograph names E. globulus, E. polybractea and E. smithii. Cineole content differs by species and batch, and a result for one oil does not carry over to another.; Name: Lemon eucalyptus (Corymbia citriodora); Note: A different plant. Its oil and the extract called PMD are used as insect repellent, not as a chest remedy. 'Oil of lemon eucalyptus' is not the same product (LactMed has a separate entry).; Name: 'Eucalyptus oil' that contains camphor; Note: Poisoning reports from India describe products labelled eucalyptus oil that contained camphor, likely made from camphor laurel.
Sustainability and conservation: Not assessed in the sources read. Widely planted.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
Aboriginal Australia	The EU oil report says the original inhabitants of Australia already used eucalyptus oil medicinally, citing a 2001 source; little reference is found in European materia medica before the second half of the 19th century.	EU assessment report on eucalyptus oil, EMA/HMPC/320282/2023
Germany, 1938	Madaus described traditional uses in cough and cold, asthma, influenza, diabetes and rheumatic diseases from Australia, India and Brazil. The EU report notes 'uncertified' antidiabetic claims.	EU assessment report on eucalyptus oil
European Union, 2014 (revised 2024)	The EU herbal committee adopted a traditional-use monograph for eucalyptus oil (revision 1 in 2024) for cough with a cold and localised muscle pain. It is 'exclusively based upon long-standing use', not trial proof.	EU herbal monograph on eucalyptus oil
Modern Germany, cineole capsules	Isolated 1,8-cineole in gastro-resistant capsules is sold in Germany as a medicine for airway infections (the branded Soledum is named in the cold and sinus papers). It is a medicine, not aromatherapy. Its legal status was not verified.	Trial papers (legal status NOT verified)

Traditional use shows how it was used. It does not show that it works or is safe today.

What is inside, and how it may work

What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.

Main compounds

Compound	Family	Where it is concentrated	Activity studied	Level of evidence
1,8-Cineole (eucalyptol) PubChem 2758	monoterpene (oxide)	Steam-distilled oil from leaves Essential oil: minimum 70% by the European Pharmacopoeia specification quoted in the EU report. One commercial E. globulus oil measured 63.1% (a 2023 analysis of one sample); other oils differ by species, place and batch.	The main active compound. Lab work shows it blocks inflammatory signals (TNF-alpha, IL-1 beta, NF-kB) and raises an antiviral signal (IRF3); it activates the cold-sensing TRPM8 nerve channel. Used as an isolated medicine in capsules. ^{40 8 23 33 44 55}	Laboratory research
alpha-Pinene PubChem 6654	monoterpene	Steam-distilled oil from leaves 0.05 to 10.0% of the oil (Ph. Eur. range quoted by the EU report); 7.3% in the one oil analysed in 2023	Minor oil component; no activity specific to eucalyptus tested in the sources read. ^{40 8 55}	Pharmacological theory
Limonene PubChem 22311	monoterpene	Steam-distilled oil from leaves 0.05 to 15.0% of the oil (Ph. Eur. range quoted by the EU report); 6.9% in the one oil analysed in 2023	Minor oil component; no activity specific to eucalyptus tested in the sources read. ^{40 8 55}	Pharmacological theory
p-Cymene PubChem 7463	monoterpene	Steam-distilled oil from leaves 7.7% in the one oil analysed in 2023	Named as an oil component; no activity tested here. ^{40 55}	Pharmacological theory
alpha-Terpineol PubChem 17100	monoterpene alcohol	Steam-distilled oil from leaves About 6.6% in one fresh-leaf oil sample (as quoted in the EU report)	Minor oil component. ⁴⁰	Pharmacological theory
Globulol PubChem 12304985	sesquiterpene alcohol	Steam-distilled oil from leaves About 10.9% in one fresh-leaf oil sample (as quoted in the EU report)	Minor oil component; no activity tested here. ⁴⁰	Pharmacological theory
Aromadendrene PubChem 11095734	sesquiterpene	Steam-distilled oil from leaves Not stated in the sources read	Named as a component of some oils; no activity tested here. ⁴⁰	Pharmacological theory
Camphor PubChem 2537	monoterpene ketone	not a normal eucalyptus component Limit of 0.1% in the oil specification quoted by the EU report	Not an intended component. Its presence in 'eucalyptus oil' suggests adulteration and adds seizure risk. ^{40 8}	Authoritative guidance

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Inflammatory signalling	NF-kB; TNF-alpha, IL-1 beta, IL-6, IL-8	In human monocytes in the lab, cineole at concentrations seen in blood lowered inflammatory messengers. Mostly from the authors who ran the cineole trials. ²³	Laboratory research
Antiviral signalling	IRF3	Cineole raised IRF3 activity (an antiviral signal) while lowering NF-kB in cell lines, nasal stem cells and cultured human nasal tissue. ^{33 23}	Laboratory research
Airway nerve channels (cooling, cough)	TRPM8, TRPA1, P2X3	A 2023 review reports eucalyptus activates TRPM8, blocks TRPA1 and lowers P2X3 in lab work, which may explain a cooling feel and less airway irritation. The review author received Procter and Gamble funding. ⁴⁴	Laboratory research
Cough reflex in animals	none identified	Cineole vapour did not significantly reduce citric-acid cough in conscious guinea pigs, while menthol and camphor did. ²⁶	Animal research
Liver drug-metabolism enzymes	CYP enzymes (cytochrome P450)	Cineole raised liver enzyme activity in rats (injection or inhalation) and shortened the effect of a sleeping drug; a 1970 five-person study suggested similar induction in people. The EU assessor called the human method weak. In test tubes, eucalyptus oil weakly blocked CYP3A4. ⁸	Animal research
Mucus and airway fluid	mucin genes (MUC2, MUC19)	A review by the cineole trial authors says cineole lowers mucin genes and mucus overproduction in lab models. Not independently confirmed in the sources read. ²³	Laboratory research
Cold- and pain-sensing nerve channels	TRPM8 (cold), TRPA1 (irritation and pain)	In human cells in the lab, 1,8-cineole switched on TRPM8 and blocked TRPA1; in animals it reduced sensory irritation caused by two TRPA1 triggers. This may explain the cooling feel. No pain study in people tests it. ⁴⁶	In vitro and animal

Absorption, metabolism and elimination

Absorption: Cineole is rapidly absorbed through the skin and mucous membranes and from the gut (EU report). In human skin from donors in a lab device, eucalyptol from a branded rub built up in the skin layers and did not cross into the receiving fluid; the authors guessed it could enter the blood in living people. Swallowed cineole reached nasal polyp tissue in 30 people.
Distribution: In rats, cineole crossed the placenta but not into milk. In nursing women, cineole taken by mouth appeared in breast milk in widely varying amounts that depended on timing (EU oil report quoting Kirsch 2012-2013).
Metabolism: 1,8-Cineole is broken down by the liver enzymes CYP3A4 (mainly) and CYP3A5 in human liver preparations. Main metabolites include 2-hydroxy- and 3-hydroxy-cineole.
Elimination: Hydroxy-cineoles are passed out in urine, partly as glucuronides (rat and rabbit data in the EU report). Half-life in people was not found in the sources read.
Bioavailability: No data for the essential oil itself; the EU documents say none were required.

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Isolated compounds versus whole extracts

The best human trials test one isolated compound, 1,8-cineole, in capsules, a medicine. Eucalyptus oil is mostly cineole (at least 70% by the pharmacopoeia standard) plus other components. Rubs, lozenges and mouthwash are mixtures with menthol, camphor or other oils. Results for one cannot be carried to another. The EU monograph for the oil rests on tradition, while the cineole capsule trials are used only as supporting evidence. A review of cineole across diseases (2023) was written with help from an employee of a cineole maker.

Nutritional composition

Eucalyptus oil is not a food or a nutrient. 1,8-cineole also occurs in food herbs such as sage and rosemary and is allowed as a food flavouring in the US (21 CFR 172.515). That says nothing about swallowing the oil, which is dangerous.

14benefits and uses looked at

55studies and sources checked

Moderate certaintybest evidence rating found

10lab markers tracked in trials

1 moderate certainty8 low certainty3 very low certainty2 not enough evidence

What was looked at

The 14 benefits and uses checked for Eucalyptus Oil, each with how strong the evidence is. Tap one to open it.

Essential oil for cough with a cold (inhaled, on the chest, in baths; traditional use)Not enough evidence
Acute sinus infection (isolated 1,8-cineole capsules)Moderate certainty
Acute bronchitis (isolated 1,8-cineole capsules)Low certainty
Common cold (a branded cineole capsule, started early)Very low certainty
Cough with colds and bronchitis (eucalyptus products, mostly combinations)Low certainty
Children's night-time cough and sleep (vapor rub ointment containing eucalyptus oil)Very low certainty
Asthma (isolated 1,8-cineole capsules added to usual medicines)Low certainty
COPD flare-ups (isolated 1,8-cineole capsules added to usual medicines)Low certainty
Chronic sinusitis and recovery after sinus surgery (a three-terpene mixture capsule)Low certainty
Pain after knee replacement surgery (eucalyptus oil inhaled)Low certainty
Pain in rheumatoid arthritis (eucalyptus oil inhaled)Low certainty
Localised muscle pain (oil on the skin or in baths; traditional use)Not enough evidence
Gum inflammation and plaque (chewing gum with eucalyptus extract)Low certainty
Inflammation, pain signals and germs (lab and animal findings)Very low certainty

Lab markers tracked in the studies

Sinus infection symptom-sum scoreBronchitis Sum ScoreCough frequencyCOPD flare-ups (frequency, severity, duration)FEV1 (forced breath out in one second)Daily steroid tablet dose in severe asthmaSelf-rated pain scoreC-reactive protein (CRP)Dental plaque scoreGum inflammation and bleeding on probing

What is Eucalyptus Oil good for?

The uses people ask about and how strong the evidence is for each. Read the certainty label first: the best results are for cineole capsules, which are a medicine, not for the bottled oil.

Cough with a cold (the oil, traditional use)Not enough evidenceThe EU accepts eucalyptus oil medicines for cough with a cold because of long use, not because trials proved it. The EU assessment report says no clinical study of the oil itself was available. Acute sinus infection (cineole capsules, a medicine)Moderate certaintyTwo German trials found cineole capsules cleared sinus symptoms faster than placebo or another herbal product over a week, and a 2023 review rated cineole among the best herbal options with moderate certainty. This is a capsule, not the oil. Acute bronchitis (cineole capsules)Low certaintyOne trial of 242 adults found more improvement and fewer coughing fits after 4 days than with placebo. It was paid for by the capsule maker and bronchitis often clears alone. Common cold (a branded cineole capsule, started early)Very low certaintyAn open-label trial with no placebo found colds were lighter and shorter in people who started the capsule sooner. It cannot show the capsule works, and the makers paid for it. Cough with colds and bronchitis (eucalyptus products, mostly combinations)Low certaintyA 2022 review of six trials found a small gain over placebo, but four trials tested combination products and the authors call the effect minimal and of uncertain importance. Children's night-time cough (a branded rub that includes eucalyptus oil)Very low certaintyIn one night-long trial of 138 children, parents rated a branded vapor rub best for cough and sleep. It is a combination, parent-rated, and it irritated more. It does not test eucalyptus alone. Asthma (cineole capsules added to usual medicines)Low certaintyTwo small German trials suggested small gains in lung function and fewer steroid tablets needed. Never use this in place of asthma medicine. COPD flare-ups (cineole capsules added to usual medicines)Low certaintyOne maker-funded trial found fewer and milder flare-ups over 6 winter months, and a 2026 ranking review put cineole first among COPD mucus-thinning drugs. Not repeated independently. Chronic sinusitis (a capsule of three terpenes with a steroid spray)Low certaintyTwo Chinese trials: one found slightly better scan scores, the other missed its main goal at week 8. A mixture, not eucalyptol alone. Pain after knee surgery (breathing the oil)Low certaintyPeople who breathed eucalyptus oil for three days reported less pain than people who breathed almond oil. The smell is hard to hide and the trial has a published correction. Pain in rheumatoid arthritis (breathing the oil)Low certaintyIn 70 people, pain was lower only in weeks 3 and 4 of a month of inhaling, and quality of life improved. One small trial. Localised muscle pain (oil on skin or in baths, traditional use)Not enough evidenceAccepted by the EU on long use. No clinical study of the oil for muscle pain was found. Gum inflammation and plaque (extract in chewing gum)Low certaintyOne 12-week Japanese trial of a chewing gum with eucalyptus extract found better plaque and gum scores than gum without it. An extract in gum, not the oil. Inflammation, pain signals and germs (lab and animal work)Very low certaintyTest-tube and animal findings only. Not shown to help people.

Benefits, one by one

Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.

Essential oil for cough with a cold (inhaled, on the chest, in baths; traditional use)

Not enough evidence

The European Union accepts eucalyptus essential oil as a traditional medicine for cough with a cold (and for muscle pain). That is based on long use. The EU assessment report says no clinical study of the oil itself is available. The oil is strong and can poison a child if swallowed, so it is not a simple home remedy.

3 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

The EU assessment report states: 'There are no clinical studies available' for the oil; it treats cineole trials as supportive.

Results

No trial result for the oil on cough.

Why this rating

Tradition only; cineole capsule trials are a different product.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

Adults and children from the EU's lower age limits.

Limits

Cannot say if the oil works. Oil can irritate airways and skin.

Why researchers looked

The oil is the steam-distilled leaf oil, high in 1,8-cineole.

Traditional use

Aboriginal Australians used eucalyptus oil; European monographs date to 1873 (EU report).

Proposed mechanism Preliminary mechanism

Cooling and airway-nerve effects (TRPM8, TRPA1) are lab ideas only.

A proposed mechanism does not show that the effect happens in people.

See the Safety tab: poisoning, seizures, laryngospasm in young children, skin allergy.

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Acute sinus infection (isolated 1,8-cineole capsules)

Moderate certainty

Two German trials found that 1,8-cineole capsules (the main chemical in eucalyptus oil, taken on its own) cleared sinus-infection symptoms faster than placebo or another herbal product over a week. A 2023 review of 47 trials rated cineole among the best herbal options for acute viral sinus infection, with moderate certainty. This is the cineole capsule, not eucalyptus oil or tea.

4 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

Kehrl 2004: 152 adults, 7 days, cineole vs placebo. Tesche 2008: 150 adults, cineole vs a five-herb combination (no placebo). The 2023 network meta-analysis (Hoang) pooled 47 trials of 18 herbal medicines and graded the evidence for acute post-viral rhinosinusitis.

Results

In Kehrl 2004 the symptom score fell from 15.6 to 3.0 with cineole by day 7, versus 9.2 with placebo. In Tesche 2008 cineole beat the five-herb product at days 4 and 7 (P < 0.0001), confirmed by sinus ultrasound.

Effect sizes as reported

Kehrl: day-7 score 3.0 vs 9.2. Tesche: day-7 score reduction 11.0 vs 8.0. Hoang: cineole among the most effective, moderate certainty (reviewers' GRADE).

Why this rating

The review rates it moderate (reviewers' own GRADE). I would not go higher: both trials come from one research group, the product's maker is linked to related trials, one trial had no placebo, sinus infections often improve alone, and the effect size is uncertain.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

Adults with acute viral sinus infection without pus.

Limits

Short trials (7 days). Funding of the two trials is not stated in the abstracts; related trials by the same group were funded by the product's maker. No long-term or child data.

Why researchers looked

Colds often settle in the sinuses. A cineole capsule is sold in Germany for this, so trials were run in people with sinus infections that were not yet pus-forming.

Traditional use

Eucalyptus leaf and oil have long been used for stuffy noses and catarrh in Europe (EU assessment reports).

Proposed mechanism Laboratory research

Lab and animal work suggests 1,8-cineole lowers inflammation signals (TNF-alpha, IL-1 beta, NF-kB) and boosts an antiviral signal (IRF3) in cells, and eucalyptus acts on cold-sensing nerve channels (TRPM8, TRPA1). These are cell or animal findings and do not prove the same happens in people.

A proposed mechanism does not show that the effect happens in people.

Mild heartburn and a rash in two people in the Kehrl trial. Cineole capsules are a medicine and are not the same as eucalyptus oil. Swallowing the oil itself has caused seizures and coma, mostly in children (see the Safety tab). Ask a doctor or pharmacist before using any cineole product.

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Acute bronchitis (isolated 1,8-cineole capsules)

Low certainty

One German trial of 242 adults with acute bronchitis found the cineole group improved more on a symptom score after 4 days, with fewer coughing fits. The trial was paid for by the capsule's maker, and acute bronchitis often clears alone.

2 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

Fischer 2013: 242 adults, multi-centre, cineole capsules vs placebo for 10 days; main outcome the Bronchitis Sum Score.

Results

After 4 days the cineole group had a bigger improvement in the score (p = 0.0383) and fewer coughing fits (p = 0.0001).

Effect sizes as reported

Bronchitis sum score p = 0.0383 and cough-fit frequency p = 0.0001 at day 4; no confidence intervals in the abstract.

Why this rating

One trial, paid for by the maker (Cassella-med, stated in the paper's acknowledgements), no replication, p-values only, and a condition that usually improves by itself.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

Adults with confirmed acute bronchitis.

Limits

Only one trial. The authors' enthusiastic conclusion ('great socioeconomic impact') goes beyond what one 10-day trial can show.

Why researchers looked

Acute bronchitis is a chest infection with cough and phlegm, usually caused by a virus. Cineole was tried because it is thought to loosen mucus and calm airway inflammation.

Traditional use

Eucalyptus has long been used for chest colds and cough in many countries.

Proposed mechanism Laboratory research

A proposed mechanism does not show that the effect happens in people.

Cineole capsules are a medicine and are not the same as eucalyptus oil. Swallowing the oil itself has caused seizures and coma, mostly in children (see the Safety tab). Ask a doctor or pharmacist before using any cineole product.

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Common cold (a branded cineole capsule, started early)

Very low certainty

A company-funded, open-label trial of a branded cineole capsule found that people who started it earlier in their cold had a lighter and shorter illness. With no placebo group, it cannot show the capsule works.

1 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

One open-label, non-randomised, exploratory trial (329 people who developed a cold), funded by the maker.

Results

People who started within 12 hours had a 38% lower overall burden of illness (p < 0.0001) and a shorter time to remission (8.9 against 10.7 days with the latest start, p < 0.05). 4.3% reported side effects judged possibly related.

Effect sizes as reported

38% lower burden of illness with the earliest start; 1.8 days shorter to remission.

Why this rating

No placebo and no randomisation, industry funded. The comparison is between people who started at different times, who may differ.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

Adults who developed a common cold.

Limits

Cannot separate the effect of the capsule from the natural course of a cold. Exploratory trial.

Why researchers looked

Colds peak in two days, so the trial enrolled people before they were ill and watched when they started the capsule.

Traditional use

Eucalyptus oil is a traditional medicine for cough with a cold (European herbal committee opinion). That is a use of the oil, not a test of cineole alone.

Proposed mechanism Mixed

In cells and in animals cineole lowers inflammation signals such as NF-kappa-B and cytokines, and in human liver tissue it is broken down mostly by CYP3A4. None of this proves how it works in a person.

A proposed mechanism does not show that the effect happens in people.

³¹

Cough with colds and bronchitis (eucalyptus products, mostly combinations)

Low certainty

A 2022 review of six trials (1,857 people) found eucalyptus products helped cough slightly more than placebo, but four of the six trials tested combination products, half of the trials had a high risk of bias, and the authors call the effect minimal and of uncertain clinical importance.

3 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

Her 2022 meta-analysis of 6 randomised trials. Pooled result: relative risk 1.45 for overall cough improvement and a weighted mean difference of 0.44 for fewer coughs. No serious adverse events; stomach upsets were common in both groups.

Results

Eucalyptus products slightly beat placebo for cough, with no serious harm seen.

Effect sizes as reported

RR 1.45 (95% CI 1.26 to 1.67) for improvement; WMD 0.44 (95% CI 0.28 to 0.60) for cough frequency.

Why this rating

Mixed products, half the trials at high risk of bias, and the authors themselves say the benefit is minimal and of uncertain importance.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

People with cough from upper airway infections and bronchitis.

Limits

Cannot give the result to eucalyptus oil, tea or cineole separately.

Why researchers looked

People use eucalyptus in lozenges, rubs and syrups for cough. This review asked whether eucalyptus really beats placebo.

Traditional use

Cough and cold use is the main traditional use of eucalyptus in Europe.

Proposed mechanism Laboratory research

Eucalyptus may act on cold-sensing nerve channels (TRPM8, TRPA1) that are linked to the cough reflex. A 1994 guinea-pig test found cineole vapour did not stop cough, while menthol and camphor did.

A proposed mechanism does not show that the effect happens in people.

^{15 26 44}

Children's night-time cough and sleep (vapor rub ointment containing eucalyptus oil)

Very low certainty

One US trial of 138 children aged 2 to 11 found parents rated a branded vapor rub (eucalyptus oil is one of its ingredients) best for night cough, stuffy nose and sleep, better than plain petroleum jelly or nothing. It was one night, parent-rated, and the smell cannot be hidden. The rub caused more skin or eye irritation. This is not a test of eucalyptus alone.

1 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

Paul 2010: partly double-blind trial; ointment or plain petrolatum or no treatment applied to the chest and neck at bedtime; parents rated symptoms the next day.

Results

The vapor rub scored best on cough, congestion and sleep. Petrolatum was no better than no treatment. Irritant side effects were more common with the rub.

Effect sizes as reported

Significant differences between groups for cough, congestion and sleep difficulty; numbers not in the abstract.

Why this rating

A combination product, one night, parent-rated, unblinded by the smell, and the abstract does not list ingredients or funders.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

Children 2 to 11 with colds.

Limits

Not a test of eucalyptus alone. Younger children were not studied.

Why researchers looked

Parents often rub a chest ointment on a coughing child. The trial asked if the ointment helps more than a plain ointment or nothing.

Traditional use

Aromatic chest rubs have been used for colds for generations.

Proposed mechanism Pharmacological theory

A cooling smell may make breathing feel easier; the effect on real airflow was not shown.

A proposed mechanism does not show that the effect happens in people.

More irritation with the rub. See the Safety tab for infants and the face.

³⁸

Asthma (isolated 1,8-cineole capsules added to usual medicines)

Low certainty

Two German trials suggest cineole capsules may help some people with asthma: a 32-person trial in severe asthma found people could cut their steroid tablets by 36% versus 7% on placebo, and a 247-person trial found small gains in lung function, symptoms and quality of life. Both are small effects from one research group.

4 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

Juergens 2003: 32 steroid-dependent adults, 12 weeks. Worth 2012: 247 adults with asthma, 6 months, cineole vs placebo plus usual medicines.

Results

Steroid dose cut: 36% with cineole vs 7% with placebo (P = 0.006); 12 of 16 vs 4 of 16 managed a reduction. In the larger trial the cineole group improved more on the combined outcome (p = 0.0027), including FEV1 (p = 0.0398).

Effect sizes as reported

Juergens: -36% vs -7% steroid dose. Worth: combined p = 0.0027; FEV1 p = 0.0398; symptoms p = 0.0325; quality of life p = 0.0475.

Why this rating

Small trials from the same group, funder not stated in the abstracts, and the sister COPD trial was funded by the maker. No independent confirmation.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

Adults with asthma, including steroid-dependent severe asthma.

Limits

Never reduce asthma medicine on your own. Inhaling eucalyptus can irritate the voice box (see Safety).

Why researchers looked

Asthma involves airway inflammation. Cineole blocked inflammatory signals in lab tests, so it was tried as an add-on.

Traditional use

Eucalyptus has a long folk use in asthma (EU report), but it is also a recognised irritant for some airways.

Proposed mechanism Laboratory research

A proposed mechanism does not show that the effect happens in people.

^{22 53 23 20}

COPD flare-ups (isolated 1,8-cineole capsules added to usual medicines)

Low certainty

A German trial in 242 people with stable COPD found that adding cineole capsules to usual medicines for 6 winter months meant fewer, shorter and milder flare-ups than placebo. A 2026 network meta-analysis ranked cineole first for fewer flare-ups among COPD mucus-thinning drugs. The trial was funded by the capsule maker and has not been repeated by an independent group we found.

3 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

Worth 2009: 242 adults with stable COPD, 6 months in winter, cineole capsules vs placebo, plus usual medicines. A later review by the same group quotes a 38.5% fall in exacerbations.

Results

In the 6-month trial, flare-ups (frequency, severity and duration combined) were significantly lower than with placebo, and lung function, breathlessness and quality of life were better; adverse events were comparable. The 2026 network meta-analysis of 18 trials (4,408 people) ranked cineole top for fewer flare-ups and fewer adverse reactions (SUCRA 87.72% and 79.04%).

Effect sizes as reported

Significant difference on the combined flare-up outcome; numbers not in the abstract (the review by the trial's authors quotes -38.5%).

Why this rating

A single trial, funded by the maker (Cassella-med; read in the paper), not repeated by independent groups, and the 2020 review is by the same authors.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

Adults with stable COPD, in winter.

Limits

One trial; numbers not in the abstract. A 2026 network meta-analysis of mucolytics in COPD appears in PubMed but I did not read it.

Why researchers looked

COPD flare-ups cause many hospital stays. Cineole was tried because it is thought to thin mucus and calm airway inflammation.

Traditional use

Eucalyptus has long been used for chronic chest complaints.

Proposed mechanism Laboratory research

A proposed mechanism does not show that the effect happens in people.

^{52 54 23}

Chronic sinusitis and recovery after sinus surgery (a three-terpene mixture capsule)

Low certainty

Two Chinese trials tested capsules of eucalyptol, limonene and pinene together with a steroid nose spray. One (174 people) found slightly better scan and endoscopy scores. The other (291 people) missed its main goal at week 8.

2 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

Two randomised trials of the same type of mixture capsule (465 people in all), neither testing eucalyptol alone.

Results

Trial 1 (174 people after sinus surgery for nasal polyps): capsule plus steroid spray beat spray alone on Lund-Mackay (p = 0.029) and Lund-Kennedy (p = 0.025) scores; side effects did not differ. Trial 2 (291 people with chronic sinusitis, double-blind): the week-8 main goal was not met (p = 0.093) although week 4 was (p = 0.012), and the scan and VAS scores did not differ at week 8.

Effect sizes as reported

Only p-values and group means in the abstracts; trial 2 improvement 4.37 against 3.85 points at week 8.

Why this rating

The week-8 main goal in the double-blind trial was missed, and the other trial did not state blinding. The mixture means the result cannot be given to eucalyptol alone.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

Adults with chronic sinusitis; some after sinus surgery for nasal polyps.

Limits

Mixture of three terpenes. Many outcomes were tested, and some single improvements may be chance.

Why researchers looked

A mixture of eucalyptol, limonene and pinene is used in some countries as a mucus-clearing capsule for sinus disease.

Proposed mechanism Mixed

Not established; the trials looked at scans, symptoms and nasal inflammation markers.

A proposed mechanism does not show that the effect happens in people.

^{43 19}

Pain after knee replacement surgery (eucalyptus oil inhaled)

Low certainty

In a Korean trial, people who breathed in eucalyptus oil for 30 minutes on three days after knee replacement reported less pain than people who breathed almond oil, and had lower blood pressure on day 2. Blood tests for inflammation (CRP, white cells) did not differ. Small trial, hard to blind because of the smell, and a correction to the paper was published in 2026.

1 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

Jun 2013: randomised trial; patients inhaled eucalyptus or almond oil during 30 minutes of passive knee movement on 3 days; pain on a 0-10 type scale, blood pressure, heart rate, CRP and white cells were measured before and after.

Results

Pain was lower on all three days with eucalyptus (P < .001); systolic and diastolic blood pressure were lower on day 2; heart rate, CRP and white cell count did not differ.

Effect sizes as reported

Pain P < .001 on all three days; blood pressure P < .05 and P = .03 on day 2; no group size in the abstract.

Why this rating

One small trial, size not in the abstract, patients can smell the difference between the oils so blinding is weak, a published correction I did not read, and no inflammation-marker change.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

Adults after total knee replacement.

Limits

Short follow-up; surgery pain also eases with time and medicines.

Why researchers looked

Eucalyptus oil is said to reduce pain, swelling and inflammation, so it was tried as a nursing aid during knee exercise after surgery.

Traditional use

Eucalyptus oil is used traditionally for muscle and joint pain (EU).

Proposed mechanism Preliminary mechanism

Cooling effect via TRPM8 nerve channels is a lab idea; the inflammation blood tests in this trial did not change.

A proposed mechanism does not show that the effect happens in people.

Breathing in strong vapours can irritate the airways in some people (vocal cord dysfunction) and is not advised for babies.

²⁴

Pain in rheumatoid arthritis (eucalyptus oil inhaled)

Low certainty

An Iranian trial of 70 people with rheumatoid arthritis found that inhaling eucalyptus oil three times a day for a month lowered pain scores in weeks 3 and 4 and improved quality of life, compared with placebo inhalation. It is one small trial where the smell makes blinding difficult.

1 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

Varkaneh 2022: 70 adults, randomised, eucalyptus oil inhaled for 5 minutes three times a day for one month, vs placebo inhalation, both with routine treatment.

Results

Pain was not different at the start, week 1 and week 2, but was lower in weeks 3 and 4 (p < 0.05); quality of life improved (P < 0.001).

Effect sizes as reported

Between-group pain difference p < 0.001 overall (analysis of covariance); week 3-4 p < 0.05; effect sizes not in the abstract.

Why this rating

Small single trial with weak blinding because of smell; no objective joint measures; registered in an Iranian registry.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

Adults with rheumatoid arthritis.

Limits

No joint swelling or blood markers reported in the abstract.

Why researchers looked

Rheumatoid arthritis pain is hard to control. A smell-based treatment was tested as an add-on to routine care.

Traditional use

Madaus (1938) listed rheumatic complaints among traditional uses (EU report).

Proposed mechanism Pharmacological theory

Not established.

A proposed mechanism does not show that the effect happens in people.

Inhaling oil is not for infants; see Safety.

⁵⁰

Localised muscle pain (oil on the skin or in baths; traditional use)

Not enough evidence

The EU accepts eucalyptus oil on the skin or in baths as a traditional medicine for localised muscle pain. This rests on long use. The EU report says no clinical study of the oil is available. The two pain trials above used inhaled oil, which is different.

2 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

No trial. The EU HMPC accepted the use as traditional on long-standing use alone.

Why this rating

Only tradition; the EU says the use is 'exclusively based upon long-standing use'.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

Adolescents and adults; children from 3 years in the EU monograph.

Limits

No evidence of benefit; irritation and allergy are possible.

Why researchers looked

Rubs and baths for aching muscles are a common household use.

Traditional use

Rheumatic complaints and localised muscle pain are traditional uses in European handbooks (Commission E 1986, ESCOP 2003, WHO 2002, cited by the EU report).

Proposed mechanism Preliminary mechanism

Cooling effect through nerve channels is an idea only.

A proposed mechanism does not show that the effect happens in people.

Do not put the oil on broken or irritated skin, and wash hands before touching the eyes (EU). Full hot baths are not for some people (see Safety). Not for babies and young children.

^{7 8}

Gum inflammation and plaque (chewing gum with eucalyptus extract)

Low certainty

A Japanese trial of 97 adults with gum inflammation found that chewing gum with eucalyptus extract (0.4% or 0.6%) for 12 weeks improved plaque, gum index, bleeding and pocket depth compared with the same gum without extract. It is one trial with a published correction (erratum). It is a specific extract in gum, not a toothpaste or mouthwash.

1 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

Nagata 2008: double-masked randomised trial; 32 people high-concentration gum, 32 low-concentration, 33 placebo gum, for 12 weeks. Measures at weeks 0, 4, 8, 12 and 14.

Results

Both eucalyptus gums improved plaque, gum index, bleeding on probing and pocket depth versus placebo gum (P < 0.05); attachment level did not change significantly.

Effect sizes as reported

P < 0.05 for four measures; actual values not in the abstract.

Why this rating

One 12-week trial in healthy adults with mild gum inflammation, no replication, an erratum I did not read, funder not stated in the abstract.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Who was studied

Healthy adults with gingivitis without deep pockets.

Limits

No long-term data; chewing gum may be unsuitable for some.

Why researchers looked

Eucalyptus extract slowed gum-disease bacteria in test tubes, so it was tested in chewing gum.

Traditional use

Not a traditional use.

Proposed mechanism Laboratory research

Antibacterial action against mouth bacteria was shown in lab tests (per the trial's background); not tested here.

A proposed mechanism does not show that the effect happens in people.

The abstract reports no side effects.

³⁵

Inflammation, pain signals and germs (lab and animal findings)

Very low certainty

In test tubes and animals, cineole and eucalyptus oil calm some inflammation signals, change pain-sensing nerve channels and slow some germs. This has not been shown to help people. Rodent studies used amounts far above any use by people, and one found a sedating effect in mice.

6 studiesNot covered. This page gives no amounts and no ways of using the oil.

Studies, doses and limits

What the trials found

No human trial of this claim. Lab: Müller 2016 (cells and cultured nasal tissue); the EU report lists many animal and cell studies.

Why this rating

Cell and animal findings only.

Form and dose studied

Not covered. This page gives no amounts and no ways of using the oil.

Limits

Lab results rarely predict effects in people.

Why researchers looked

Eucalyptus has been studied as an antiseptic and anti-inflammatory plant.

Traditional use

Antisepsis was among Köhler's 1873 uses (EU report).

Proposed mechanism Laboratory research

Cineole blocked inflammatory signals (TNF-alpha, IL-1 beta, NF-kB) and raised an antiviral signal (IRF3) in human cells and nasal tissue in the lab.

A proposed mechanism does not show that the effect happens in people.

Do not use eucalyptus oil as an antiseptic on wounds without medical advice.

^{33 14 46 42 27 8}

Connections to the rest of health

How Eucalyptus Oil connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.

Explore every connection: goals, body systems, organs, symptoms, genes

Kind of connection Connected to Search

A. Wellness goals

Connected to	Kind of connection	Evidence status	Context	Studies
Immune Support	Traditional use	Not enough evidence	Essential oil for cough with a cold (inhaled, on the chest, in baths; traditional use): The European Union accepts eucalyptus essential oil as a traditional medicine for cough with a cold (and for muscle pain). That is based on long use. The EU assessment report says no clinical study of the oil itself is available. The oil is strong and can poison a child if swallowed, so it is not a simple home remedy.	^{7 8 6}
Immune Support	Potential benefit	Moderate certainty	Acute sinus infection (isolated 1,8-cineole capsules): Two German trials found that 1,8-cineole capsules (the main chemical in eucalyptus oil, taken on its own) cleared sinus-infection symptoms faster than placebo or another herbal product over a week. A 2023 review of 47 trials rated cineole among the best herbal options for acute viral sinus infection, with moderate certainty. This is the cineole capsule, not eucalyptus oil or tea.	^{25 47 17 33}
Inflammation Balance	Potential benefit	Low certainty	Pain after knee replacement surgery (eucalyptus oil inhaled): In a Korean trial, people who breathed in eucalyptus oil for 30 minutes on three days after knee replacement reported less pain than people who breathed almond oil, and had lower blood pressure on day 2. Blood tests for inflammation (CRP, white cells) did not differ. Small trial, hard to blind because of the smell, and a correction to the paper was published in 2026. Pain in rheumatoid arthritis (eucalyptus oil inhaled): An Iranian trial of 70 people with rheumatoid arthritis found that inhaling eucalyptus oil three times a day for a month lowered pain scores in weeks 3 and 4 and improved quality of life, compared with placebo inhalation. It is one small trial where the smell makes blinding difficult.	^{24 50}
Joint Support	Potential benefit	Low certainty	Pain in rheumatoid arthritis (eucalyptus oil inhaled): An Iranian trial of 70 people with rheumatoid arthritis found that inhaling eucalyptus oil three times a day for a month lowered pain scores in weeks 3 and 4 and improved quality of life, compared with placebo inhalation. It is one small trial where the smell makes blinding difficult.	⁵⁰
Inflammation Balance	Traditional use	Not enough evidence	Localised muscle pain (oil on the skin or in baths; traditional use): The EU accepts eucalyptus oil on the skin or in baths as a traditional medicine for localised muscle pain. This rests on long use. The EU report says no clinical study of the oil is available. The two pain trials above used inhaled oil, which is different.	^{7 8}
Digestive Support	Potential benefit	Low certainty	Gum inflammation and plaque (chewing gum with eucalyptus extract): A Japanese trial of 97 adults with gum inflammation found that chewing gum with eucalyptus extract (0.4% or 0.6%) for 12 weeks improved plaque, gum index, bleeding and pocket depth compared with the same gum without extract. It is one trial with a published correction (erratum). It is a specific extract in gum, not a toothpaste or mouthwash.	³⁵
Immune Support	Preliminary mechanism	Very low certainty	Inflammation, pain signals and germs (lab and animal findings): In test tubes and animals, cineole and eucalyptus oil calm some inflammation signals, change pain-sensing nerve channels and slow some germs. This has not been shown to help people. Rodent studies used amounts far above any use by people, and one found a sedating effect in mice.	^{33 14 46 42 27 8}
Inflammation Balance	Preliminary mechanism	Very low certainty	Inflammation, pain signals and germs (lab and animal findings): In test tubes and animals, cineole and eucalyptus oil calm some inflammation signals, change pain-sensing nerve channels and slow some germs. This has not been shown to help people. Rodent studies used amounts far above any use by people, and one found a sedating effect in mice.	^{33 14 46 42 27 8}

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Nervous system	Adverse effect or risk	Low certainty	Seizures and drowsiness after oil exposure, mainly children; pooled analysis of 110 cases. Preparation or compound: Eucalyptus essential oil (swallowed, inhaled or on skin)	^{37 49}
Respiratory system	Adverse effect or risk	Very low certainty	Vocal cord dysfunction in one woman; laryngospasm risk in infants. Preparation or compound: Inhaled eucalyptus oil	^{20 8}
Skin	Adverse effect or risk	Very low certainty	Contact eczema and allergy reported; frequency unknown. Preparation or compound: Eucalyptus oil on skin	^{7 8 16}
Liver	Drug or supplement interaction	Not enough evidence	Liver enzyme induction in rats; one small volunteer study; EU says no interaction reported. Preparation or compound: 1,8-cineole	⁸
Pregnancy and breastfeeding	Contraindication	Not enough evidence	Not recommended: no data. Cineole crosses the placenta in rats and passes into breast milk after oral intake. Preparation or compound: Oil	^{7 8}
Respiratory System	Biological association	Not enough evidence	Studied for: Essential oil for cough with a cold (inhaled, on the chest, in baths; traditional use) Studied for: Acute sinus infection (isolated 1,8-cineole capsules)	^{7 8 6 25 47 17 33 9 23 31 15 26 44 38 22 53 20 52 54 43 19}
Immune System	Biological association	Very low certainty	Studied for: Common cold (a branded cineole capsule, started early) Studied for: Inflammation, pain signals and germs (lab and animal findings)	^{31 33 14 46 42 27 8}
Musculoskeletal System	Biological association	Low certainty	Studied for: Pain after knee replacement surgery (eucalyptus oil inhaled) Studied for: Pain in rheumatoid arthritis (eucalyptus oil inhaled)	^{24 50 7 8}
Nervous System	Biological association	Low certainty	Studied for: Pain after knee replacement surgery (eucalyptus oil inhaled)	²⁴
Integumentary System	Biological association	Not enough evidence	Studied for: Localised muscle pain (oil on the skin or in baths; traditional use)	^{7 8}
Digestive System	Biological association	Low certainty	Studied for: Gum inflammation and plaque (chewing gum with eucalyptus extract)	³⁵

E. Health conditions

Connected to	Kind of connection	Evidence status	Context	Studies
Essential oil poisoning in children	Adverse effect or risk	Documented risk	Hospital series of toddlers; seizures and coma reported. Preparation or compound: Swallowed eucalyptus oil	^{49 51 10 4}
Seizures	Adverse effect or risk	Low certainty	Pooled review of 110 cases and case series. Preparation or compound: Eucalyptus oil (swallowed, inhaled or on skin)	^{37 29 41}
Acute sinus infection (rhinosinusitis)		Moderate certainty	Two German trials and a 2023 network meta-analysis. Preparation or compound: Isolated 1,8-cineole capsules (not the oil)	^{25 47 17}
COPD		Low certainty	One maker-funded trial and a 2026 ranking review. Preparation or compound: Isolated 1,8-cineole capsules (not the oil)	^{52 54}
Asthma		Low certainty	Two small German trials. Preparation or compound: Isolated 1,8-cineole capsules (not the oil)	^{22 53}

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
Sinus infection symptom-sum score	Biological association	Moderate certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{25 47 17}
Bronchitis Sum Score	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁹
Cough frequency	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	¹⁵
COPD flare-ups (frequency, severity, duration)	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{52 23}
FEV1 (forced breath out in one second)	Biological association	Low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	⁵³
Daily steroid tablet dose in severe asthma	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	²²
Self-rated pain score	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{24 50}
C-reactive protein (CRP)	Biological association	Low certainty	Measured in trials: no-change. A lab change is not the same as a health benefit.	²⁴
Dental plaque score	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	³⁵
Gum inflammation and bleeding on probing	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	³⁵

J. Genes, receptors and enzymes

Connected to	Kind of connection	Evidence status	Context	Studies
IRF3 (interferon regulatory factor 3)	Preliminary mechanism	In vitro	Antiviral signal raised by cineole in cells and cultured nasal tissue.	³³
TRPM8, TRPA1 (TRP channels), P2X3	Preliminary mechanism	In vitro	Cold-sensing and irritation channels on airway nerves; eucalyptus activates TRPM8 and blocks TRPA1 in lab work.	⁴⁴
CYP3A4 and CYP3A5	Preliminary mechanism	In vitro	Liver enzymes that break down 1,8-cineole; eucalyptus oil weakly blocked CYP3A4 in a lab test.	⁸
MUC2 and MUC19 (mucin genes)	Preliminary mechanism	In vitro	Lowered by cineole in lab models, per a review by the cineole trial authors.	²³

K. Biological pathways

Connected to	Kind of connection	Evidence status	Context	Studies
NF-kB inflammatory signalling	Preliminary mechanism	In vitro	Lowered by 1,8-cineole in lab cell studies.	^{23 33}

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
1,8-Cineole (eucalyptol)		Laboratory	Main component of the oil; broken down by liver enzyme CYP3A4. Preparation or compound: Eucalyptus oil	^{55 32}
1,8-Cineole (eucalyptol)	Biological association	In vitro	The main active compound. Lab work shows it blocks inflammatory signals (TNF-alpha, IL-1 beta, NF-kB) and raises an antiviral signal (IRF3); it activates the cold-sensing TRPM8 nerve channel. Used as an isolated medicine in capsules. Preparation or compound: Steam-distilled oil from leaves	^{40 8 23 33 44 55}
alpha-Pinene	Biological association	Pharmacological theory	Minor oil component; no activity specific to eucalyptus tested in the sources read. Preparation or compound: Steam-distilled oil from leaves	^{40 8 55}
Limonene	Biological association	Pharmacological theory	Minor oil component; no activity specific to eucalyptus tested in the sources read. Preparation or compound: Steam-distilled oil from leaves	^{40 8 55}
p-Cymene	Biological association	Pharmacological theory	Named as an oil component; no activity tested here. Preparation or compound: Steam-distilled oil from leaves	^{40 55}
alpha-Terpineol	Biological association	Pharmacological theory	Minor oil component. Preparation or compound: Steam-distilled oil from leaves	⁴⁰
Globulol	Biological association	Pharmacological theory	Minor oil component; no activity tested here. Preparation or compound: Steam-distilled oil from leaves	⁴⁰
Aromadendrene	Biological association	Pharmacological theory	Named as a component of some oils; no activity tested here. Preparation or compound: Steam-distilled oil from leaves	⁴⁰
Camphor	Biological association	Authoritative guidance	Not an intended component. Its presence in 'eucalyptus oil' suggests adulteration and adds seizure risk. Preparation or compound: not a normal eucalyptus component	^{40 8}

Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 25, 2026).

Evidence at a glance: what changed in 10 lab markers

Tap a number to show only those markers. Counts are markers, not people.

Inflammatory1 Other81

The evidence

The research centre for Eucalyptus Oil. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.

Evidence by outcome

Essential oil for cough with a cold (inhaled, on the chest, in baths; traditional use) 3 studies Not enough evidence Acute sinus infection (isolated 1,8-cineole capsules) 4 studies · 302 people in trials Moderate certainty Acute bronchitis (isolated 1,8-cineole capsules) 2 studies · 242 people in trials Low certainty Common cold (a branded cineole capsule, started early) 1 study Very low certainty Cough with colds and bronchitis (eucalyptus products, mostly combinations) 3 studies Low certainty Children's night-time cough and sleep (vapor rub ointment containing eucalyptus oil) 1 study · 138 people in trials Very low certainty Asthma (isolated 1,8-cineole capsules added to usual medicines) 4 studies · 279 people in trials Low certainty COPD flare-ups (isolated 1,8-cineole capsules added to usual medicines) 3 studies · 242 people in trials Low certainty Chronic sinusitis and recovery after sinus surgery (a three-terpene mixture capsule) 2 studies · 465 people in trials Low certainty Pain after knee replacement surgery (eucalyptus oil inhaled) 1 study Low certainty Pain in rheumatoid arthritis (eucalyptus oil inhaled) 1 study · 70 people in trials Low certainty Localised muscle pain (oil on the skin or in baths; traditional use) 2 studies Not enough evidence Gum inflammation and plaque (chewing gum with eucalyptus extract) 1 study · 97 people in trials Low certainty Inflammation, pain signals and germs (lab and animal findings) 6 studies Very low certainty

Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).

How we rate evidence

High certainty

Several well-run trials or reviews agree; further research is unlikely to change the picture much.

Moderate certainty

Good trials point the same way, but some doubt remains.

Low certainty

Small, short or inconsistent trials. The finding could change with better research.

Very low certainty

Very little or very weak human data. Treat as a possibility only.

Mixed findings

Trials or reviews disagree with each other.

Not enough evidence

Not enough human research to say either way.

Evidence against

Good research found no benefit, or found harm.

We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We checked every PubMed paper against its PubMed record and read its abstract, and read the EMA, Poison Control and ASPCA pages. The EMA documents were read as text extracted by software. We checked the plant names in GBIF and the main compound in PubChem. We did not find or read a LiverTox, LactMed, FDA or NCCIH statement.

Study library: every study we checked 55

Design Research type Year from Search

Study	Design	People	Product, dose, length	Result
ASPCA Animal Poison Control Center 2026 ASPCA: Eucalyptus (toxic and non-toxic plants list) ASPCA web page (read 2026-10-25) · Source	Authoritative guidance	n/a	n/a	Lists eucalyptus as toxic to dogs, toxic to cats and toxic to horses. Names the toxic principle as essential oils: eucalyptol. Clinical signs listed: salivation, vomiting, diarrhea, depression, weakness. Gives the ASPCA Poison Control line, 888-426-4435, and says to call your vet if a pet may have swallowed a toxic substance. Lists eucalyptus as toxic to dogs, toxic to cats and toxic to horses. Names the toxic principle as essential oils: eucalyptol. Clinical signs listed: salivation, vomiting, diarrhea, depression, weakness. Gives the ASPCA Poison Control line, 888-426-4435, and says to call your vet if a pet may have swallowed a toxic substance. Methods, limits and funding Outcomes: Safety information for the public Limitations: A plant listing. It does not measure risk from diffused or skin-applied oil, and it gives no amounts. Funding and conflicts: n/a Read: full-text
Boyle 2011 Clinically significant interaction between warfarin and popular cough lozenges 'Fisherman's Friend'. BMJ Case Rep · PMID 22675107 · DOI	Case report	1 A 67-year-old man taking warfarin (Scotland)	Cough lozenges containing eucalyptus oil, menthol and liquorice (combination), about 1 month combination lozenge Not shown on this page About 1 month	Using the lozenges for about a month was followed by a clear fall of INR to below the target range, which stayed stable after stopping them. Probable interaction with a combination lozenge. Methods, limits and funding Outcomes: Blood-clotting test (INR) Limitations: One case. The lozenge has several ingredients (the EU report names eucalyptus oil, menthol and liquorice), so eucalyptus cannot be blamed on its own; warfarin is cleared mostly by CYP2C9, not CYP3A4 (EU assessor's comment). Funding and conflicts: Authors declare no competing interests. Read: abstract
Cal 2008 Ex vivo skin absorption of terpenes from Vicks VapoRub ointment. Med Sci Monit · PMID 18668006	Laboratory research human cadaver skin	Human cadaver skin in a diffusion chamber	Vicks VapoRub ointment (eucalyptol, menthol, camphor, alpha-pinene, beta-pinene) Branded ointment Not shown on this page Minutes	The terpenes did not pass through the skin into the receiving fluid in this set-up. Eucalyptol built up most in the stratum corneum and in the deeper skin. The authors say the terpenes could easily enter the blood circulation in living people. Eucalyptol enters skin readily from a rub Methods, limits and funding Outcomes: How much of each terpene entered the skin layers Limitations: Skin from dead donors in a lab device. The conclusion about blood is the authors' guess, not a measurement. Funding and conflicts: Not stated in the abstract. Read: abstract
Day 1997 Eucalyptus oil poisoning among young children: mechanisms of access and the potential for prevention. Aust N Z J Public Health · PMID 9270157 · DOI	Survey	109 Parents of children under 5 with actual or suspected eucalyptus oil swallowing, Victoria, Australia	Eucalyptus oil products (vaporiser solutions, oil preparations) Essential oil products 9-month survey	Eucalyptus oil was a leading agent in hospitalisation for poisoning of under-5s in Victoria. In the survey, 90 incidents involved vaporiser solutions, 15 eucalyptus oil preparations and the rest other medicinal products; 74% got to the oil through a home vaporiser, most often at floor level. The authors say amounts swallowed are usually small but the reported toxic dose range is wide, so a medical check is needed after swallowing. Home vaporiser solutions were the way most toddlers got to eucalyptus oil Methods, limits and funding Outcomes: How children reached the oil; how common the problem was Limitations: Victoria in the 1990s. Rules and products have changed since. Funding and conflicts: Not stated in the abstract. Read: abstract
Douros 2016 Herb-Induced Liver Injury in the Berlin Case-Control Surveillance Study. Int J Mol Sci · PMID 26784183 · DOI	Case series	198 198 hospital cases of liver injury in Berlin, 2002-2011	Herbal medicines (Eucalyptus globulus in one case) unspecified	Ten of 198 cases were judged probably or possibly herbal; Eucalyptus globulus was named once as 'possible' (valerian five times). No liver failure or death. One possible case; the EU report found the details too thin (no product or dose; clarithromycin also taken). Methods, limits and funding Outcomes: Which herbs were a possible cause Limitations: Possible causality does not prove harm. The EU assessor said the case does not support a liver-harm signal. Funding and conflicts: Not stated in the abstract. Read: abstract
European Medicines Agency 2016 EMA public summary EMA/HMPC/288003/2014 (first published and last updated 05/12/2016; page read 2026-10-25) · Source	Authoritative guidance	n/a	n/a	The committee concluded that, on long-standing use, eucalyptus oil can be used for cough with the common cold and for localised muscle pain. It said the basis is traditional use: there is insufficient evidence from clinical trials, but effectiveness is plausible and the medicines have been used safely for at least 30 years. It looked at cineole trials in bronchitis and asthma but could draw no firm conclusion because they did not use the oil. Do not give to children with a history of seizures, or to children under 30 months because of a risk of voice-box spasm (the newer 2024 monograph says under 24 months). Traditional use accepted; trial evidence for the oil itself is insufficient Methods, limits and funding Outcomes: What the EU herbal committee concluded about eucalyptus oil medicines Limitations: A 2016 public summary, older than the 2024 revised monograph; the monograph's age limits are the newer figure. Funding and conflicts: Regulator document (no commercial funding). Read: full-text
European Medicines Agency 2024 EU herbal monograph on Eucalyptus globulus Labill.; E. polybractea R.T. Baker; E. smithii R.T. Baker, aetheroleum (Final, Revision 1) EMA · Source	Authoritative guidance		leaf (essential oil) Not shown on this page	Traditional use only: relief of cough with a cold and relief of localised muscle pain (oil by mouth, inhaled, on skin, in baths). Contraindicated in children under 24 months (laryngospasm), in children with a history of seizures, and with allergy to the oil or cineole. Pregnancy and breastfeeding not recommended. Interactions: none reported. Side effects: allergic reactions including severe ones, stomach upset (by mouth), contact eczema (skin), frequency unknown. Overdose: stomach pain, vomiting, breathing problems, drowsiness, loss of consciousness, convulsions, constricted pupils. Methods, limits and funding Limitations: Read in full (11 pages), text extracted by software. It is a traditional-use document, not proof of benefit; the doses are not repeated on this page. Funding and conflicts: Regulator document (no commercial funding). Read: full-text
European Medicines Agency 2024 Assessment report on Eucalyptus globulus Labill.; E. polybractea; E. smithii, aetheroleum (Final, Revision 1) EMA · Source	Authoritative guidance		leaf (essential oil) Not shown on this page	No clinical studies of the oil itself; the cineole trials are treated as supportive. Reviews animal CYP-induction data and a small human study (Jori 1970), seizure and poisoning case series, skin allergy, breast-milk transfer of cineole, camphor adulteration of Indian 'eucalyptus oil', and advice not to apply to the face of babies (reflex glottis spasm). Methods, limits and funding Limitations: Read selectively (safety, interaction, pharmacokinetic, regulatory and history sections of 49 pages), text extracted by software. Older studies are described second-hand. Funding and conflicts: Regulator document (no commercial funding). Read: full-text
Fischer 2013 Efficacy of cineole in patients suffering from acute bronchitis: a placebo-controlled double-blind trial. Cough · PMID 24261680 · DOI	Controlled trial	242 Adults with confirmed acute bronchitis (multi-centre)	Cineole capsules (the product name is not given in the abstract) Isolated compound (1,8-cineole) in capsules Not shown on this page 10 days · vs Placebo capsules	After 4 days the cineole group had improved more on the Bronchitis Sum Score (p = 0.0383), and cough fits were fewer (p = 0.0001). Registered as ISRCTN37784439. Fewer cough fits after 4 days than with placebo Methods, limits and funding Outcomes: Bronchitis Sum Score (cough and related symptoms) Limitations: The overall score gain is only just below p = 0.05. Acute bronchitis usually gets better by itself, and the abstract does not show how fast the placebo group recovered after day 4. Funding and conflicts: Funded by a grant from Cassella-med, Cologne, Germany, the maker of cineole products (read in the full text on Europe PMC). The authors declare no competing interests. Registration: ISRCTN37784439 Read: abstract and full text (funding statement)
Flaman 2001 Unintentional exposure of young children to camphor and eucalyptus oils. Paediatr Child Health · PMID 20084213 · DOI	Case series	251 Children who swallowed essential oil products, Toronto poison centre, 1995-1997	Eucalyptus oil, camphorated oil, a vaporising liquid and Vicks VapoRub (all swallowed) essential oil products	251 children: 50 swallowed eucalyptus oil, 90 a vapor rub, 93 a vaporising liquid. Cough, vomiting and cough with vomiting were most common. Two had seizures and recovered. The literature search found 18 reports with vomiting, lethargy, coma and seizures; one child died. Essential oils can be harmful, even life-threatening, if swallowed by children. Methods, limits and funding Outcomes: Symptoms; literature search Limitations: Poison-centre telephone data; includes combination products. Funding and conflicts: Not applicable. Read: abstract
GBIF backbone: ACCEPTED GBIF species match: Eucalyptus radiata A.Cunn. ex DC. · Source	Authoritative guidance		Not shown on this page	Accepted species name, family Myrtaceae. Not named in the EU oil monograph, which covers E. globulus, E. polybractea and E. smithii. Methods, limits and funding Limitations: Name check only. Funding and conflicts: Regulator document (no commercial funding). Read: full-text
GBIF backbone: ACCEPTED GBIF species match: Eucalyptus globulus Labill. · Source	Authoritative guidance		Not shown on this page	Accepted species name, family Myrtaceae. Methods, limits and funding Limitations: Name check only. Funding and conflicts: Regulator document (no commercial funding). Read: full-text
Government of Western Australia 2026 Essential oils: safety and first aid (Healthy WA) Healthy WA (read 2026-10-25; page shows no review date) · Source	Authoritative guidance n/a	n/a	n/a	Says eucalyptus oil, clove oil, tea tree oil and aromatherapy oils are commonly used essential oils; children are particularly susceptible; as little as 2 mL (less than half a teaspoon) of eucalyptus oil can cause significant poisoning in an infant; essential oils are not safe to consume. First aid: do not induce vomiting; call the Poisons Information Centre on 13 11 26. Says eucalyptus oil, clove oil, tea tree oil and aromatherapy oils are commonly used essential oils; children are particularly susceptible; as little as 2 mL (less than half a teaspoon) of eucalyptus oil can cause significant poisoning in an infant; essential oils are not safe to consume. First aid: do not induce vomiting; call the Poisons Information Centre on 13 11 26. Methods, limits and funding Outcomes: What a state health department tells the public about swallowed essential oils Limitations: A public advice page, not a study. The page shows no review date. Funding and conflicts: n/a Read: summary-only
Greiner 2013 1,8-Cineol inhibits nuclear translocation of NF-κB p65 and NF-κB-dependent transcriptional activity. Biochim Biophys Acta · PMID 23872422 · DOI	Laboratory research cells	Human cell lines (U373, HeLa) and human blood cells	1,8-cineol Isolated compound Not given in the abstract · vs Untreated cells	1,8-cineol lowered NF-kappa-B activity in cells stimulated with a bacterial toxin (LPS) and reduced movement of the p65 protein into the nucleus. It also lowered NF-kappa-B target gene activity and, in human blood cells, nuclear p65. The abstract describes Soledum as the clinically approved drug that contains the compound. A lab explanation for an anti-inflammatory effect Methods, limits and funding Outcomes: NF-kappa-B activity and movement into the nucleus; target gene expression Limitations: Cells in dishes. It does not show the same happens in a person who takes a capsule or breathes vapour. Funding and conflicts: Not stated in the abstract. Read: abstract
Her 2022 Efficacy and Safety of Eucalyptus for Relieving Cough: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Integr Complement Med · PMID 35294302 · DOI	Meta-analysis	1857 People with cough from upper respiratory infections or bronchitis (6 randomised trials)	Eucalyptus globulus products; four of six trials used combination formulas unspecified (products varied) Not shown on this page not extracted · vs Placebo	Eucalyptus products beat placebo for overall cough improvement (relative risk 1.45) and lowered cough frequency (weighted mean difference 0.44). Three of six trials were low risk of bias, three high risk. No serious adverse events; mild to moderate stomach symptoms were common in both groups. Overall cough improvement RR 1.45; cough frequency WMD 0.44. The authors call the efficacy 'minimal and of uncertain clinical importance'. (RR 1.45 (95% CI 1.26 to 1.67); WMD 0.44 (95% CI 0.28 to 0.60)) Methods, limits and funding Outcomes: Improvement or resolution of overall cough, cough frequency, adverse events Limitations: Most trials tested combination formulas, so the effect cannot be given to eucalyptus alone. Half the trials were at high risk of bias. Funding and conflicts: Not stated in the abstract. Read: abstract
Higgins 2015 Eucalyptus oil: contact allergy and safety. Contact Dermatitis · PMID 25752915 · DOI	Case report	Skin allergy report (Australia)	Eucalyptus oil on skin essential oil, topical	PubMed lists the title only; no abstract is available, so the findings were not read. Not read. Methods, limits and funding Outcomes: Contact allergy Limitations: Title only. The EU assessment report cites other eucalyptus contact-allergy reports (eight reports in one review). Funding and conflicts: Not applicable. Read: summary-only
Hoang 2023 Herbal Medicines for Rhinosinusitis: A Systematic Review and Network Meta-analysis. Curr Allergy Asthma Rep · PMID 36609950 · DOI	Network meta analysis	Adults and children with different forms of rhinosinusitis; 47 randomised trials of 18 herbal medicines	Several herbal medicines, including a cineole product ("Cineole") Various · vs Placebo or other treatment	For acute post-viral rhinosinusitis, Cineole and Pelargonium sidoides were the most effective treatments for controlling symptoms (moderate certainty). The authors say more trials with enough people and long follow-up are needed. Cineole ranked among the best of the herbal medicines tested for acute post-viral rhinosinusitis, with moderate certainty Methods, limits and funding Outcomes: Symptom scores and quality of life, graded for certainty (GRADE) Limitations: The abstract does not say how many cineole trials fed this result. Network comparisons rank treatments indirectly. Funding and conflicts: Not stated in the abstract. Read: abstract
Hoch 2023 1,8-cineole (eucalyptol): A versatile phytochemical with therapeutic applications across multiple diseases. Biomed Pharmacother · PMID 37696087 · DOI	Narrative review human and lab	Review of cineole across diseases	1,8-cineole (eucalyptol) Isolated compound	Says clinical trials in COPD, asthma, bronchitis and rhinosinusitis show benefit, and that uses in depression, epilepsy, ulcers, diarrhoea, heart disease and diabetes are potential only. Calls for study of safety and better formulations. Review; the non-respiratory uses are not shown in people Methods, limits and funding Outcomes: Summary of clinical trials and lab data Limitations: A review by authors with one employee of the cineole maker Cassella-med, who "provided guidance during the writing" (stated in the paper). Funding and conflicts: One author is employed by Cassella-med GmbH (maker of a cineole product). The others report no conflicts. Read: abstract
Hu 2025 Efficacy and safety of intranasal corticosteroids combined with mucoactive drugs for chronic rhinosinusitis. Int Immunopharmacol · PMID 40911992 · DOI	Controlled trial	291 Adults with chronic rhinosinusitis (13 hospitals in China)	Eucalyptol + limonene + pinene enteric capsules (ELP) plus budesonide nose spray Mixture of three isolated terpenes in enteric capsules Not shown on this page 8 weeks (visits at weeks 4 and 8) · vs Placebo capsules plus the same budesonide nose spray (double-blind)	The capsule group improved more at week 4 (p = 0.012), but at week 8, the planned main point, the difference was not significant (p = 0.093). The Lund-Mackay scan score and the VAS scale did not differ at week 8. Some single symptoms did improve more (nasal congestion, postnasal drip, runny nose, loss of smell). The effect on CT score was seen in smokers (p = 0.022). The main goal at week 8 was not met; some single symptoms and a smokers subgroup improved Methods, limits and funding Outcomes: Major Symptom Score change from the start to week 8 (the main goal); other symptoms; scans Limitations: A near-miss on the main goal, with many extra tests afterwards, so the positive findings are less secure. A three-terpene mixture, not eucalyptol alone. Funding and conflicts: The authors declare no competing financial interests. Read: abstract
Huggins 2004 Eucalyptus as a specific irritant causing vocal cord dysfunction. Ann Allergy Asthma Immunol · PMID 15478393 · DOI	Case report	1 A 46-year-old woman (USA)	Inhaled dried eucalyptus leaves (blind challenge) plant, inhaled minutes · vs Water, ammonia, pine oil	The vocal cords closed inappropriately within minutes of eucalyptus (and not with the other irritants). Allergy tests were negative, so the reaction looked like irritation, not allergy. This condition can mimic asthma. Eucalyptus triggered vocal cord dysfunction in one woman. Methods, limits and funding Outcomes: Camera look at the vocal cords during inhalation Limitations: One person. Funding and conflicts: Not stated in the abstract. Read: abstract
Ittyachen 2019 Eucalyptus oil poisoning: two case reports. J Med Case Rep · PMID 31685016 · DOI	Case report	2 Two adult men who accidentally swallowed eucalyptus oil (India)	Eucalyptus oil swallowed Essential oil Not given in the abstract Admitted for 4 days	Both came in with seizures and severe metabolic acidosis, were treated in intensive care with bicarbonate and supportive care, and left hospital on day 4. The authors say seizures are unusual in adults but are not rare in children, and call for warning labels on all eucalyptus oil products. Seizures and acid-base upset in adults who swallowed the oil, with recovery Methods, limits and funding Outcomes: Symptoms and recovery Limitations: Two cases only. Funding and conflicts: No competing interests declared. Read: abstract
Juergens 2003 Anti-inflammatory activity of 1.8-cineol (eucalyptol) in bronchial asthma: a double-blind placebo-controlled trial. Respir Med · PMID 12645832 · DOI	Controlled trial	32 Adults with steroid-dependent severe asthma	Cineole capsules (the product name is not given in the abstract) Isolated compound (1,8-cineole) in small gut-soluble capsules Not shown on this page 12 weeks (after a 2-month run-in) · vs Placebo capsules	Steroid doses were reduced by 36% in the cineole group and by 7% in the placebo group, p = 0.006. Twelve of 16 people on cineole and 4 of 16 on placebo managed a reduction (p = 0.012). More patients were able to cut their steroid tablets on cineole than on placebo Methods, limits and funding Outcomes: How far the daily dose of oral steroid tablets could be reduced (steroid-sparing effect) Limitations: Only 32 people. Steroid tapering was done by the trial team; people should never change steroid doses on their own. Funding and conflicts: Funding is not stated in the abstract; the full text was not read. Read: abstract
Juergens 2020 New Perspectives for Mucolytic, Anti-inflammatory and Adjunctive Therapy with 1,8-Cineole in COPD and Asthma: Review on the New Therapeutic Approach. Adv Ther · PMID 32200535 · DOI	Narrative review human and lab	Review of lab studies and trials of cineole in COPD and asthma	1,8-cineole (eucalyptol) Isolated compound Not shown on this page	The review states that earlier randomised trials of cineole capsules (6 months) improved uncontrolled asthma and cut COPD flare-ups by 38.5% in winter. It also summarises lab work in human cells: NF-kappa-B control, lower cytokines, and an added effect with budesonide in vitro. Narrative review that supports the trial results; its 38.5% figure comes from the COPD trial Methods, limits and funding Outcomes: Summary of lab mechanisms and earlier trials Limitations: Narrative review, not systematic. Two authors (Worth, Juergens) ran the trials it describes. Conflict statement not read. Funding and conflicts: Not stated in the abstract. Read: abstract
Jun 2013 Effect of eucalyptus oil inhalation on pain and inflammatory responses after total knee replacement: a randomized clinical trial. Evid Based Complement Alternat Med · PMID 23853660 · DOI	Controlled trial	Adults after total knee replacement surgery (number of people not given in the abstract)	Eucalyptus oil, inhaled (a whole essential oil, not isolated cineole) Essential oil Not shown on this page 3 consecutive days · vs Almond oil inhaled the same way	Pain scores were lower with eucalyptus oil than with almond oil on all three days (p < .001). Systolic and diastolic blood pressure were lower on day 2. Heart rate, CRP and white blood cell count did not differ. A correction notice for this paper was published in 2026 (not read). Lower pain scores after knee surgery with eucalyptus oil smell than with almond oil smell Methods, limits and funding Outcomes: Pain on a 0 to 10 style visual scale, blood pressure, heart rate, CRP and white blood cell count Limitations: The two oils smell different, so people probably knew which they were getting, and pain is a rating people give themselves. The abstract gives no numbers. It is a whole oil, not cineole by itself. Funding and conflicts: Not stated in the abstract; the full text was not read. Read: abstract
Kehrl 2004 Therapy for acute nonpurulent rhinosinusitis with cineole: results of a double-blind, randomized, placebo-controlled trial. Laryngoscope · PMID 15064633 · DOI	Controlled trial	152 Adults with acute non-pus rhinosinusitis (sinus infection that is not yet pus-filled)	Cineole capsules (the product name is not given in the abstract) Isolated compound (1,8-cineole) in capsules Not shown on this page 7 days · vs Placebo capsules	The average symptom score started at 15.6 in both groups. In the cineole group it was 6.9 after 4 days and 3.0 after 7 days. In the placebo group it was 12.2 and 9.2. The authors call the difference clinically relevant and significant. Two people on cineole had mild side effects (heartburn and a rash). Faster fall in sinus symptom score than with placebo over 7 days Methods, limits and funding Outcomes: Sum score of symptoms and signs after 4 and 7 days Limitations: A short trial with an overall symptom score that mixes what people feel with what the doctor finds. The abstract reports no tests of blinding. Funding and conflicts: Funding is not stated in the abstract; the full text was not read. Read: abstract
Laude 1994 The antitussive effects of menthol, camphor and cineole in conscious guinea-pigs. Pulm Pharmacol · PMID 7827436 · DOI	Animal research animal	13 Conscious guinea pigs	Menthol, camphor and cineole vapours isolated compounds Not shown on this page 5 minutes · vs Air	Menthol and camphor reduced cough; cineole at the concentrations tested had no significant effect. Cineole did not stop cough in this animal test. Methods, limits and funding Outcomes: Cough after citric-acid challenge Limitations: Animal study from 1994; one set of concentrations. Funding and conflicts: Not stated in the abstract. Read: abstract
Liapi 2007 Antinociceptive properties of 1,8-Cineole and beta-pinene, from the essential oil of Eucalyptus camaldulensis leaves, in rodents. Planta Med · PMID 17893834 · DOI	Animal research mouse and rat	Mice and rats	1,8-cineole and beta-pinene (from Eucalyptus camaldulensis leaves) Isolated compounds Not given in the abstract Acute tests · vs Morphine, naloxone	Cineole gave pain-test effects "comparable to morphine" in both tests, with a synergy with morphine, and naloxone did not block it. Beta-pinene acted differently. Pain-test effect in rodents Methods, limits and funding Outcomes: Tail-flick and hot-plate pain tests Limitations: Animal tests only. The authors still had mechanism work in progress. Funding and conflicts: Not stated in the abstract. Read: abstract
MacKenzie 2023 Determination of orally administered 1,8-Cineol in nasal polyp tissues from chronic rhinosinusitis patients using gas chromatography: mass spectrometry. Sci Rep · PMID 36869061 · DOI	Pharmacokinetic study	30 Adults with chronic rhinosinusitis with nasal polyps awaiting surgery	Orally given 1,8-cineole medicine Isolated compound Not given in the abstract 14 days before surgery	Cineole was detected in nasal polyp tissue after 14 days by mouth, with no clear link to body weight or BMI. The authors say this indicates it spreads through the body after swallowing. Shows that swallowed cineole reaches nasal tissue in people Methods, limits and funding Outcomes: Amount of cineole in nasal polyp tissue (GC-MS) Limitations: Detection only; it does not show benefit. Funded by the maker of the product. Funding and conflicts: Cassella-med (the maker) funded the study and supplied the medicine, and two authors work for it. The paper says the company had no influence on sampling, analysis or data. Read: abstract
Mathew 2017 Eucalyptus oil inhalation-induced seizure: A novel, underrecognized, preventable cause of acute symptomatic seizure. Epilepsia Open · PMID 29588965 · DOI	Case series	10 10 people with seizures after inhaling eucalyptus oil, three hospitals in India	Eucalyptus oil vapour Essential oil Not given in the abstract	Eight people had generalised tonic-clonic seizures and two had complex partial seizures. The authors say doctors rarely ask about eucalyptus oil in first-time seizures and want to raise awareness. Seizure after breathing eucalyptus oil vapour has been reported Methods, limits and funding Outcomes: Seizure type Limitations: Case report series; the abstract gives no amounts or ages. Funding and conflicts: Not stated in the abstract. Read: abstract
Mathew 2020 Essential oil-related status epilepticus: A small case series study. J Am Coll Emerg Physicians Open · PMID 33145540 · DOI	Case series	3 Three adults with status epilepticus linked to essential oils (India, 2018-2019)	Eucalyptus oil swallowed (two cases); balms with eucalyptus and camphor on the skin (one case) Essential oil and balms Not given in the abstract	Two adults had generalised status epilepticus after swallowing eucalyptus oil. The third had focal status epilepticus after rubbing on balms containing eucalyptus and camphor. The authors advise asking about essential oil exposure. Three adults with prolonged seizures linked to eucalyptus oil Methods, limits and funding Outcomes: Seizure type Limitations: Three cases. The balm contained camphor too, so eucalyptus cannot be blamed alone. Funding and conflicts: Not stated in the abstract. Read: abstract
Michalsen 2024 The impact of cineole treatment timing on common cold duration and symptoms: Non-randomized exploratory clinical trial. PLoS One · PMID 38236839 · DOI	Clinical trial	329 Adults who developed a common cold (out of 522 enrolled before they were ill)	Soledum (CNL-1976), a branded cineole capsule Isolated compound (1,8-cineole) in capsules Not shown on this page Up to about 15 days	People who started within 12 hours had the lowest burden of illness, 38% lower overall (p < 0.0001), and a shorter time to remission (8.9 days against 10.7 days for the latest starters, p < 0.05). Side effects judged possibly related to the capsule were reported by 4.3% of people. Starting the capsule earlier in a cold went with a lighter and shorter cold Methods, limits and funding Outcomes: Burden of illness over time (WURSS-11 symptom survey) Limitations: No placebo group and no randomisation, so earlier starters may differ from later starters, and colds get better by themselves. It cannot show the capsule works. Industry-funded. Funding and conflicts: All authors received financial support from Cassella-med or MCM Klosterfrau (the makers). Some authors report fees from other drug companies. Registration: EudraCT 2020-000860-51 Read: abstract
Miyazawa 2001 Oxidation of 1,8-cineole, the monoterpene cyclic ether originated from eucalyptus polybractea, by cytochrome P450 3A enzymes in rat and human liver microsomes. Drug Metab Dispos · PMID 11159812	Laboratory research human and rat liver tissue	Human and rat liver microsomes; enzymes made in insect cells	1,8-cineole Isolated compound · vs Enzyme inhibitors	Human liver microsomes turned 1,8-cineole into 2-exo-hydroxy-1,8-cineole, mainly by CYP3A4 (and about one quarter as fast by CYP3A5). The ketoconazole block and the link with CYP3A4 amounts in 18 human livers support this. The authors call it a very good CYP3A4 substrate. Cineole is broken down in the liver mainly by CYP3A4 Methods, limits and funding Outcomes: How the liver enzymes change cineole Limitations: Lab enzymes. It does not show that cineole changes the levels of other drugs. Funding and conflicts: Not stated in the abstract. Read: abstract
Müller 2016 1,8-Cineole potentiates IRF3-mediated antiviral response in human stem cells and in an ex vivo model of rhinosinusitis. Clin Sci (Lond) · PMID 27129189 · DOI	Laboratory research in-vitro	Human cell lines, nasal stem cells and human nasal tissue in the lab	Isolated 1,8-cineole isolated compound Not shown on this page lab · vs Untreated cells	Cineole raised IRF3 antiviral signalling and lowered NF-kB inflammatory signalling in cells and in cultured nasal tissue. Lab finding only. Methods, limits and funding Outcomes: Antiviral (IRF3) and inflammatory (NF-kB) signals Limitations: Not a human trial. The abstract names the Soledum product; funder not stated. Funding and conflicts: Not stated in the abstract. Read: abstract
NCBI Taxonomy NCBI Taxonomy: Eucalyptus globulus (taxid 34317) · Source	Authoritative guidance		Not shown on this page	Taxid 34317, species, eudicots (checked through the NCBI E-utilities API). Methods, limits and funding Limitations: Name check only. Funding and conflicts: Regulator document (no commercial funding). Read: full-text
Nagata 2008 Effect of eucalyptus extract chewing gum on periodontal health: a double-masked, randomized trial. J Periodontol · PMID 18672986 · DOI	Controlled trial	97 Healthy adults with gum inflammation but no deep pockets (Japan)	Chewing gum with eucalyptus extract (0.4% or 0.6%) unspecified Not shown on this page 12 weeks · vs Gum without eucalyptus extract	Both eucalyptus gum groups improved more than placebo on plaque, gum index, bleeding and pocket depth (P < 0.05), but not on attachment level. Statistically better plaque, gingival index, bleeding and probing depth at 12 weeks. Methods, limits and funding Outcomes: Plaque, gum index, bleeding on probing, pocket depth, attachment level Limitations: One 12-week trial. A correction (erratum) was published later (J Periodontol 2008;79(10):2010); I did not read what it changed. Funder not stated in the abstract. Not a toothpaste or mouthwash. Funding and conflicts: Not stated in the abstract. Read: abstract
National Library of Medicine 2026 PubChem GHS classification for 1,8-Cineole (CID 2758) PubChem PUG-View, retrieved 2026-10-25 · Source	Authoritative guidance n/a	n/a	n/a	Aggregated from 2,296 reports by companies in 17 notifications: H226 flammable liquid and vapour (98.7%) and H317 may cause an allergic skin reaction (84.2%). 8 of 2,296 reports said it does not meet GHS hazard criteria. Aggregated from 2,296 reports by companies in 17 notifications: H226 flammable liquid and vapour (98.7%) and H317 may cause an allergic skin reaction (84.2%). 8 of 2,296 reports said it does not meet GHS hazard criteria. Methods, limits and funding Outcomes: Hazard classes companies report for the pure chemical Limitations: These are classes for the pure chemical, as notified by companies, not measured rates in users. Funding and conflicts: n/a Read: full-text
Panda 2021 Clinico-laboratory characteristics and outcome of patients with eucalyptus oil-induced/provoked seizures: A case series and systematic review of the published patients. Trop Doct · PMID 34282989 · DOI	Systematic review	110 110 reported cases (49 children) of seizures linked to eucalyptus oil, plus five new children	Eucalyptus oil by skin, inhalation or swallowing Essential oil	Inhalation was the most common route among the 110 cases. The most common seizure type was generalised tonic-clonic. Most had an uneventful recovery, and adults were less likely to have prolonged or repeated seizures or need intensive care or ventilation. Seizures after eucalyptus oil have been reported from skin, vapour and swallowing Methods, limits and funding Outcomes: Type, treatment and outcome of seizures Limitations: A pooled case report review, which cannot show how common seizures are. Funding and conflicts: Not stated in the abstract. Read: abstract
Paul 2010 Vapor rub, petrolatum, and no treatment for children with nocturnal cough and cold symptoms. Pediatrics · PMID 21059712 · DOI	Controlled trial	138 Children aged 2 to 11 with night-time cough and cold symptoms (USA)	Vapor rub ointment (a branded rub; combination product, includes eucalyptus oil among other ingredients) rubbed on chest and neck topical ointment Not shown on this page One night · vs Petrolatum ointment, or no treatment	Parents rated the vapor rub best for cough, congestion and sleep; it beat no treatment on every score except runny nose, and beat petrolatum on cough, sleep and the combined score. Irritant side effects were more common with the rub. Rub scored best; petrolatum was no better than nothing. Methods, limits and funding Outcomes: Parent-rated cough, congestion, sleep difficulty Limitations: A combination product, so no effect can be given to eucalyptus oil alone. Parent-rated, only partly blinded (the smell is hard to hide), one night of use. The abstract does not list the ingredients or funder. Funding and conflicts: Funding and ingredients not stated in the abstract (grants listed in PubMed are from the NIH clinical research centre programme). Manufacturer involvement not verified. Read: abstract
Poison Control (National Capital Poison Center) 2026 Poison Control (National Capital Poison Center): Essential oils, poisonous when misused poison.org web page (read 2026-10-25; undated) · Source	Authoritative guidance	n/a	n/a	Says eucalyptus oil is used for soothing effects when inhaled, for example during a cold or cough, and that if swallowed it can cause seizures. Says pure essential oils are potent; children have thin skin and immature livers, which may make them more susceptible to toxic effects; essential oils may interact with medications; allergy to an essential oil is a very real possibility; and bottles should be locked up out of the sight and reach of children and pets. Essential oil products are not well regulated, so species, strength and contaminants can be hard to know. Says eucalyptus oil is used for soothing effects when inhaled, for example during a cold or cough, and that if swallowed it can cause seizures. Says pure essential oils are potent; children have thin skin and immature livers, which may make them more susceptible to toxic effects; essential oils may interact with medications; allergy to an essential oil is a very real possibility; and bottles should be locked up out of the sight and reach of children and pets. Essential oil products are not well regulated, so species, strength and contaminants can be hard to know. Methods, limits and funding Outcomes: Safety information for the public Limitations: General page for all essential oils (its worked cases are a camphor child and a lavender child); the eucalyptus lines are brief. Funding and conflicts: n/a Read: full-text
PubChem (NCBI) PubChem compound records: 1,8-cineole (CID 2758), alpha-pinene (6654), limonene (22311), p-cymene (7463), alpha-terpineol (17100), globulol (12304985), aromadendrene (11095734), camphor (2537) · Source	Authoritative guidance		Not shown on this page	Compound identifiers confirmed by name search through the PubChem PUG REST service. Methods, limits and funding Limitations: Identifier check only. Funding and conflicts: Regulator document (no commercial funding). Read: full-text
Sai Chandar 2021 Eucalyptus Oil-Induced Seizures in Children: A Single-Center Prospective Study. Cureus · PMID 33927923 · DOI	Case series	17 Children with a first seizure or breakthrough seizure after eucalyptus oil, one hospital in South India (2 years)	Eucalyptus oil drops swallowed in water or milk Essential oil Not shown on this page Follow-up 6 to 9 months	All 17 children had a generalised tonic-clonic seizure about 20 minutes (median; range 10 to 120) after swallowing the oil. Median age was 3.75 years. Scans were normal in all; none had another seizure in 6 to 9 months of follow-up. The authors call it an under-recognised cause of seizures in children. Swallowed eucalyptus oil caused seizures in 17 children, all recovered Methods, limits and funding Outcomes: Seizure type, timing, scans, EEG and recurrence Limitations: Small, single-centre series. Unknown how many children swallow the oil without seizures. Funding and conflicts: No competing interests declared. Read: abstract
Santos 2000 Antiinflammatory and antinociceptive effects of 1,8-cineole a terpenoid oxide present in many plant essential oils. Phytother Res · PMID 10861965 · DOI	Animal research rat and mouse	Rats and mice	1,8-cineole Isolated compound Not shown on this page Acute tests · vs Vehicle; naloxone in one test	Cineole reduced inflammation in rat paw and granuloma tests and pain behaviour in mouse formalin and acetic acid tests. Naloxone did not reverse the pain effect, so it does not seem to work through opioid receptors. It also reduced movement and lengthened pentobarbital sleeping time in mice, which the authors read as a possible depressant effect on the nervous system. Less inflammation and pain behaviour in rodents; also a sedating effect in mice Methods, limits and funding Outcomes: Paw swelling, pain behaviour, movement, sleeping time Limitations: Animal work at doses far above any use by people. Funding and conflicts: Not stated in the abstract. Read: abstract
Sima 2025 A Multicenter, Randomized, Controlled Clinical Trial on the Efficacy and Safety of Eucalyptol, Limonene, and Pinene Enteric Capsules in the Treatment of Chronic Rhinosinusitis With Nasal Polyps Postoperatively. Clin Transl Allergy · PMID 41327929 · DOI	Controlled trial	174 Adults with chronic rhinosinusitis with nasal polyps, after sinus surgery (multi-centre, China)	Eucalyptol + limonene + pinene enteric capsules (ELP), a three-terpene mixture, together with a steroid nose spray Mixture of three isolated terpenes in enteric capsules Not given in the abstract 12 weeks · vs Steroid nose spray alone (assigned 1:2, so more people got the capsules)	The capsule-plus-spray group had greater improvement on CT scan (Lund-Mackay) and endoscopy (Lund-Kennedy) scores (p = 0.029 and 0.025), shorter nose-clearance time at week 4 (p = 0.015) and lower levels of several inflammation markers in a subgroup. Side effects did not differ between groups. Registered as ChiCTR2200055224. Slightly better scan and endoscopy scores when a three-terpene capsule was added to the nose spray Methods, limits and funding Outcomes: Scan and endoscopy scores, nose-clearance test, symptom questionnaire (SNOT-22), inflammation markers in nasal fluid, side effects Limitations: This tests a mixture of three terpenes, so the effect cannot be given to eucalyptol alone. The abstract does not say whether anyone was blinded. Many outcomes were tested, and only some improved. Funding and conflicts: The authors declare no conflicts of interest. Registration: ChiCTR2200055224 Read: abstract
Stinson 2023 Modulation of transient receptor potential (TRP) channels by plant derived substances used in over-the-counter cough and cold remedies. Respir Res · PMID 36755306 · DOI	Systematic review in-vitro	Lab and animal literature on menthol, camphor, eucalyptus, turpentine and thymol	Eucalyptus (and other plant substances) acting on nerve-ending channels mixed	The review reports that eucalyptus activates the cold-sensing TRPM8 channel, blocks TRPA1 and lowers P2X3, which may explain a cooling feel and less airway irritation; it is a lab mechanism, not proof of benefit. Plausible mechanism, lab level. Methods, limits and funding Outcomes: TRP channel effects Limitations: Review of lab work. Funding and conflicts: One author received funding from Procter & Gamble for this work (stated in the paper). Read: abstract
Suresh 2025 Fatal Eucalyptus Oil Poisoning in an Adult Male: A Case Report With Comprehensive Autopsy and Histopathological Findings. Cureus · PMID 40432665 · DOI	Case report	1 An adult man who swallowed 15 mL of eucalyptus oil stored in a cough-syrup bottle (India)	Eucalyptus oil swallowed by mistake Essential oil Not shown on this page Died in hospital	Seizures began within minutes, then unresponsiveness and weak breathing; he had a cardiac arrest, was revived, kept seizing, and died at a second hospital. The post-mortem showed damage to the tongue, windpipe, stomach and gut, lung emphysema, fatty liver change and kidney damage. The authors stress public awareness of potential lethality. A fatal outcome after swallowing 15 mL of pure oil Methods, limits and funding Outcomes: Clinical course and post-mortem findings Limitations: One case. Funding and conflicts: No funding or competing interests declared. Read: abstract
Takaishi 2012 1,8-cineole, a TRPM8 agonist, is a novel natural antagonist of human TRPA1. Mol Pain · PMID 23192000 · DOI	In vitro and animal cells and animal	Human TRP channels in cells; a sensory irritation test in animals	1,8-cineole Isolated compound Not given in the abstract · vs Other compounds, including 1,4-cineole	1,8-cineole switched on TRPM8 (the cool sensor) and blocked human TRPA1 (a pain and irritation sensor), and in animals it reduced sensory irritation caused by two TRPA1 triggers. 1,4-cineole, a close relative, activated both channels. The authors suggest it is a natural TRPA1 antagonist with possible analgesic effects. A lab and animal explanation for the cooling feeling and for reduced irritation Methods, limits and funding Outcomes: Activity on cold-sensing (TRPM8) and pain-sensing (TRPA1) channels Limitations: Cells and animals only. No pain study in people tests this. Funding and conflicts: Not stated in the abstract. Read: abstract
Tesche 2008 The value of herbal medicines in the treatment of acute non-purulent rhinosinusitis. Results of a double-blind, randomised, controlled trial. Eur Arch Otorhinolaryngol · PMID 18437408 · DOI	Controlled trial	150 Adults with acute viral sinus infection (Germany)	Isolated 1,8-cineole vs a five-ingredient herbal combination isolated compound Not shown on this page 7 days · vs A five-component herbal combination (not a placebo)	Cineole lowered the score by 11.0 at day 7 versus 8.0 with the combination (P < 0.0001). The ultrasound result agreed. Cineole beat the other herbal product; both were safe for 7 days. Methods, limits and funding Outcomes: Symptom-sum score; sinus ultrasound Limitations: No placebo group, so it shows cineole beat another herbal product, not placebo. Funder not stated in the abstract. Funding and conflicts: Not stated in the abstract. Read: abstract
The Royal Children's Hospital Melbourne 2021 Eucalyptus Oil Poisoning (Clinical Practice Guideline, PIC endorsed) RCH Clinical Practice Guidelines (last updated July 2021; read 2026-10-25) · Source	Authoritative guidance n/a	n/a	n/a	Small swallowed amounts of pure oil (5 mL or more) can lead to severe symptoms. 2 to 3 mL can cause mild central nervous system depression (drowsiness, dizziness, unsteadiness) and 5 mL or more significant depression with coma. Symptoms usually start within 30 minutes but may be delayed up to 4 hours, and usually settle within 24 hours. Main things to watch are CNS depression and breathing problems. The guideline lists the Australian Poisons Information Centre number 13 11 26 for 24-hour advice. Small swallowed amounts of pure oil (5 mL or more) can lead to severe symptoms. 2 to 3 mL can cause mild central nervous system depression (drowsiness, dizziness, unsteadiness) and 5 mL or more significant depression with coma. Symptoms usually start within 30 minutes but may be delayed up to 4 hours, and usually settle within 24 hours. Main things to watch are CNS depression and breathing problems. The guideline lists the Australian Poisons Information Centre number 13 11 26 for 24-hour advice. Methods, limits and funding Outcomes: What a children's hospital guideline says about eucalyptus oil poisoning Limitations: An Australian hospital guideline for clinicians; it states no author. It was read through a page-reading tool, not as a PDF. Funding and conflicts: n/a Read: summary-only
Tibballs 1995 Clinical effects and management of eucalyptus oil ingestion in infants and young children. Med J Aust · PMID 7651249 · DOI	Case series	109 Children under 9 admitted to the Royal Children's Hospital, Melbourne, 1981 to 1992	Eucalyptus oil swallowed by accident Essential oil Not shown on this page Hospital stay mean 22 hours	Of 109 children (mean age 23.5 months), 59% had effects. 31 (28%) had depressed consciousness: 27 drowsy, 3 unconscious after 5 to 10 mL, and 1 unconscious with weak breathing after an estimated 75 mL. 37% vomited, 15% were unsteady, and 11% had lung disease. All recovered. Among 27 children with known doses, effects scaled with the volume (nil after a mean of 1.7 mL; major poisoning after 7.5 mL). The author concludes that significant drowsiness should be expected after 5 mL or more of 100% oil and minor drowsiness may follow 2 to 3 mL. Swallowing a teaspoon or so of pure oil can make a toddler seriously unwell Methods, limits and funding Outcomes: Symptoms and signs, the amount swallowed, and hospital stay Limitations: Retrospective hospital review, so children seen were the ones sick enough to come in. Doses were often estimated. The oil is not pure cineole. Funding and conflicts: Not stated in the abstract. Read: abstract
Varkaneh 2022 The effect of eucalyptus inhalation on pain and the quality of life in rheumatoid arthritis. Contemp Clin Trials Commun · PMID 36060153 · DOI	Controlled trial	70 Adults with rheumatoid arthritis (Iran)	Eucalyptus oil inhaled for 5 minutes, 3 times a day (as reported) essential oil, inhaled Not shown on this page 1 month · vs Placebo inhalation	Pain was lower than control only from weeks 3 and 4, and quality of life rose (P < 0.001). Both groups also used routine treatment. Lower pain in weeks 3 and 4; better quality of life. Methods, limits and funding Outcomes: Pain (numerical scale), quality of life (SF-12) Limitations: Small single trial; the smell of eucalyptus is hard to blind; the abstract is unclear on the exact oil and species. Funding and conflicts: No conflicts of interest declared by the authors. Registration: IRCT20160110025929N15 Read: abstract
Webb 1993 Eucalyptus oil poisoning in childhood: 41 cases in south-east Queensland. J Paediatr Child Health · PMID 8240865 · DOI	Case series	41 Children under 14 with swallowed eucalyptus oil (Brisbane, 1984-1991)	Swallowed eucalyptus oil essential oil, swallowed Not shown on this page	Eighty percent were symptom-free, including four children who swallowed more than 30 mL. No child needed advanced life support and the amount taken did not predict symptoms. The authors thought the oil may be less toxic than believed. Most children had no symptoms. Methods, limits and funding Outcomes: Symptoms on arrival to hospital Limitations: Retrospective; an older report that sits against the other series. Shows that outcomes vary widely, not that it is safe. Funding and conflicts: Not applicable. Read: abstract
Worth 2009 Concomitant therapy with Cineole (Eucalyptole) reduces exacerbations in COPD: a placebo-controlled double-blind trial. Respir Res · PMID 19624838 · DOI	Controlled trial	242 Adults with stable COPD (multi-centre, winter-time)	Cineole capsules (the product name is not given in the abstract) Isolated compound (1,8-cineole) in capsules Not shown on this page 6 months · vs Placebo capsules, with usual COPD medicines in both groups	Flare-ups were significantly lower with cineole than with placebo for frequency, severity and duration combined. Lung function, breathlessness and quality of life, taken together, were also significantly better than with placebo. The abstract says side effects were comparable in both groups. Registered as ISRCTN07600011. Fewer COPD flare-ups over 6 months, as an add-on to usual treatment Methods, limits and funding Outcomes: Number, severity and length of flare-ups (exacerbations) combined; lung function, breathlessness and quality of life Limitations: One trial from one research group; the abstract gives no numbers for individual outcomes. It tests one cineole product, so it says nothing about eucalyptus oil, vapour or cannabis. Funding and conflicts: Funded by a grant from Cassella-med, Cologne, Germany, the maker of cineole products (read in the full text on Europe PMC). The authors declare no competing interests. Registration: ISRCTN07600011 Read: abstract and full text (funding statement)
Worth 2012 Patients with asthma benefit from concomitant therapy with cineole: a placebo-controlled, double-blind trial. J Asthma · PMID 22978309 · DOI	Controlled trial	247 Adults with confirmed asthma (multi-centre)	Cineole capsules (the product name is not given in the abstract) Isolated compound (1,8-cineole) in capsules Not shown on this page 6 months · vs Placebo capsules, with usual asthma treatment	The cineole group improved more on the combined measure than the placebo group (p = 0.0027). Single measures were also significant: FEV1 (p = 0.0398), asthma symptoms (p = 0.0325) and asthma quality of life (p = 0.0475). The abstract gives no effect sizes. Better lung function, symptoms and quality of life in asthma, as an add-on to usual treatment Methods, limits and funding Outcomes: Lung function, asthma symptoms and asthma quality of life (combined primary measure) Limitations: The single-measure p-values are close to 0.05. The abstract gives no sizes of change. The same research group, and a similar design, as the COPD trial. Funding and conflicts: Funding is not stated in the abstract; the full text was not read. Read: abstract
Zhao 2026 Efficacy and safety of mucolytic agents in patients with chronic obstructive pulmonary disease: a systematic review and network meta-analysis. BMC Pulm Med · PMID 41688985 · DOI	Network meta analysis	4408 Adults with COPD; 18 randomised trials of mucolytic drugs	Several mucolytic drugs including cineole Various · vs Placebo, usual care or another drug	For reducing flare-ups and for the lowest rate of side effects, cineole ranked highest (SUCRA 87.72% and 79.04%). Other drugs ranked first for lung function (erdosteine) and inflammation markers (tyloxapol). The authors call for larger multi-centre trials with long-term safety data. Cineole ranked first for fewer flare-ups and fewer side effects among COPD mucolytics, in an indirect ranking Methods, limits and funding Outcomes: Inflammation markers, lung function, ROS, flare-up rates and side effects Limitations: Rankings are not proof of a difference; the abstract does not say how many cineole trials were included. Probably few, and mostly the trials above. Funding and conflicts: The authors declare no competing interests. Read: abstract
Čmiková 2023 Chemical Composition and Biological Activities of Eucalyptus globulus Essential Oil. Plants (Basel) · PMID 36903935 · DOI	Chemical analysis plant oil	One commercial Eucalyptus globulus essential oil	Eucalyptus globulus essential oil Leaf oil	1,8-cineole was 63.1% of the oil, with p-cymene 7.7%, alpha-pinene 7.3% and limonene 6.9%; monoterpenes made up 99.2% of the oil. Cineole was the main compound, 63.1%, in this one oil Methods, limits and funding Outcomes: Composition by GC and GC/MS Limitations: One oil sample. Other oils differ by species, place and batch. Funding and conflicts: The authors declare no conflict of interest. Read: abstract

What we do not know yet

What the evidence supports: cineole capsules are moderate for acute sinus infection and low for bronchitis, asthma and COPD; the oil itself has only tradition and small pain trials.
No clinical trial of eucalyptus oil for cough, colds or sinus problems was found in the EU assessment report.
No study of diffused oil, of bronchospasm in asthma, or of oil in pets was found.
No study of pregnancy, breastfeeding or newborns beyond milk-transfer measurements.
No LiverTox, LactMed, FDA or NCCIH statement was read.

How new research is added

New studies are found by a saved PubMed search and are placed in a review queue. A person reads each one before it is added.

Lab markers

What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".

Inflammatory 1

●

C-reactive protein (CRP)

No clear change in trials

A blood marker that rises with inflammation.

Low certainty

Results and what it means

Why it was measured

Used to test whether pain relief came with less inflammation.

Statistical vs. clinical meaning

Pain fell while inflammation markers did not, so the pain result may not reflect less inflammation.

Safety implication

None.

Study	Result	People	Product
²⁴	CRP and white cell count did not differ between eucalyptus and almond oil inhalation	Adults after total knee replacement	Eucalyptus oil inhaled, 3 days

²⁴

Other 9

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Sinus infection symptom-sum score

Lowered in trials

A doctor-rated score adding up headache, face tenderness, blocked nose, discharge and general condition.

Moderate certainty

Results and what it means

Why it was measured

It is the main yardstick for how a sinus infection is going.

Statistical vs. clinical meaning

Large score changes in short trials; sinus infections often improve alone, and one comparator was another herbal product.

Safety implication

None.

Study	Result	People	Product
²⁵	Mean score 15.6 at the start; 6.9 at day 4 and 3.0 at day 7 with cineole, versus 12.2 and 9.2 with placebo	152 adults with acute non-pus-forming sinus infection	Isolated cineole capsules vs placebo, 7 days
⁴⁷	Reduction in score 6.7 (day 4) and 11.0 (day 7) with cineole, versus 3.6 and 8.0 with a five-herb product (P < 0.0001)	150 adults with acute viral sinus infection	Cineole vs five-component herbal combination, 7 days

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Bronchitis Sum Score

Lowered in trials

A score adding up the main symptoms of acute bronchitis, such as cough, phlegm and chest pain.

Low certainty

Results and what it means

Why it was measured

Main outcome of the acute bronchitis trial.

Statistical vs. clinical meaning

Statistically significant; abstract gives no score values or confidence intervals.

Safety implication

None.

Study	Result	People	Product
⁹	Cineole group improved more by day 4 (p = 0.0383); coughing fits fell more (p = 0.0001)	242 adults with acute bronchitis	Cineole capsules vs placebo, 10 days

⁹

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Cough frequency

Lowered in trials

How often a person coughs, counted by diary or recorder.

Low certainty

Results and what it means

Why it was measured

Cough is the symptom people most want relieved.

Statistical vs. clinical meaning

The authors call the effect minimal and of uncertain clinical importance.

Safety implication

None.

Study	Result	People	Product
¹⁵	Eucalyptus products lowered cough frequency vs placebo: weighted mean difference 0.44 (95% CI 0.28 to 0.60)	People with cough from respiratory infections (6 trials)	Eucalyptus products, mostly combinations, vs placebo

¹⁵

▼

COPD flare-ups (frequency, severity, duration)

Lowered in trials

Episodes when COPD symptoms suddenly worsen, often needing extra medicine or hospital care.

Low certainty

Results and what it means

Why it was measured

Flare-ups drive hospital stays and lung decline in COPD.

Statistical vs. clinical meaning

Numbers are not in the abstract; one funder-linked trial.

Safety implication

Adverse events were similar to placebo.

Study	Result	People	Product
⁵²	Frequency, severity and duration of flare-ups were significantly lower with cineole than placebo over 6 months; lung function and breathlessness improved	242 adults with stable COPD	Cineole capsules plus usual medicines vs placebo, 6 months

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▲

FEV1 (forced breath out in one second)

Raised in trials

The amount of air you can blow out in the first second, a basic lung-function test.

Low certainty

Results and what it means

Why it was measured

A common measure of how open the airways are.

Statistical vs. clinical meaning

Small but statistically significant gains in one trial; clinical importance not given in the abstract.

Safety implication

None.

Study	Result	People	Product
⁵³	FEV1 improved more with cineole than placebo (p = 0.0398); asthma symptoms p = 0.0325; quality of life p = 0.0475	247 adults with asthma	Cineole capsules plus usual medicines vs placebo, 6 months

⁵³

▼

Daily steroid tablet dose in severe asthma

Lowered in trials

How much prednisolone tablet a person with severe asthma needs each day.

Low certainty

Results and what it means

Why it was measured

Needing less steroid shows less inflammation and avoids steroid side effects.

Statistical vs. clinical meaning

A small trial; steroid reductions must only be made by a doctor.

Safety implication

Do not cut steroid tablets on your own.

Study	Result	People	Product
²²	Daily steroid tablet dose fell by 36% with cineole versus 7% with placebo (P = 0.006); 12 of 16 vs 4 of 16 managed a reduction (P = 0.012)	32 steroid-dependent adults with severe asthma	Cineole capsules vs placebo, 12 weeks

²²

▼

Self-rated pain score

Lowered in trials

A scale on which a person rates pain from none to the worst.

Low certainty

Results and what it means

Why it was measured

Pain is what patients most want relieved.

Statistical vs. clinical meaning

Self-rated and open to smell-related bias.

Safety implication

None.

Study	Result	People	Product
²⁴	Pain lower on all 3 days after knee replacement with eucalyptus oil inhalation than with almond oil inhalation (P < .001)	Adults after total knee replacement	Eucalyptus oil vs almond oil inhaled for 30 minutes, 3 days
⁵⁰	Pain lower than control in weeks 3 and 4 (p < 0.05); no difference in weeks 0 to 2	70 adults with rheumatoid arthritis	Eucalyptus oil inhaled vs placebo, 1 month

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Dental plaque score

Lowered in trials

A score of how much sticky bacterial film is on the teeth.

Low certainty

Results and what it means

Why it was measured

Plaque causes gum disease and decay.

Statistical vs. clinical meaning

Plaque scores are a stand-in for gum health; the rinse result is for a mixture.

Safety implication

None.

Study	Result	People	Product
³⁵	Plaque improved more with eucalyptus-extract gum than placebo gum over 12 weeks (P < 0.05)	97 adults with gingivitis	Eucalyptus-extract chewing gum vs plain gum, 12 weeks

³⁵

▼

Gum inflammation and bleeding on probing

Lowered in trials

Scores for red, swollen or bleeding gums.

Low certainty

Results and what it means

Why it was measured

Gum inflammation is the first sign of gum disease.

Statistical vs. clinical meaning

Clinical gum measures, but one gum trial and a mixed rinse.

Safety implication

None.

Study	Result	People	Product
³⁵	Gingival index, bleeding on probing and pocket depth improved vs placebo gum (P < 0.05); attachment level did not	97 adults with gingivitis	Eucalyptus-extract chewing gum, 12 weeks

³⁵

Safety

What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.

Main points to know 10

Do not swallow eucalyptus oil: a small amount can poison a child, with drowsiness, vomiting and seizures. Hospital and poison-centre reports describe young children who swallowed eucalyptus oil, often from a vaporiser liquid or a bottle left within reach. In a Melbourne series of 109 children, 59% had symptoms: drowsiness or unconsciousness in 28%, vomiting in 37%, unsteadiness in 15% and lung problems in 11%. All recovered. A Queensland series found 80% of 41 children had no symptoms, so outcomes vary widely. A Western Australian health page says about half a teaspoon has caused significant poisoning in an infant. Any swallowing needs medical advice at once. In adults, seizures, deep coma and death are reported, including a death after 15 mL swallowed by mistake. Some products sold as eucalyptus oil in India were found to contain camphor. Case series ^{49 51 10 4 21 45 13 48 39}
Never put eucalyptus oil or rubs on or near the face of a baby or young child. The EU contraindicates eucalyptus oil medicines in children under 24 months because strong-smelling oils can cause a reflex spasm of the voice box (laryngospasm), which can briefly stop breathing. The EU assessment report also says ointments containing eucalyptus should not be put on or near the face, especially the nose, of babies and very young children. The EU adds that children with a history of seizures, with or without fever, must not use it. An older 2016 EU public summary gave 30 months; the newer 2024 monograph says 24 months. Authoritative guidance ^{7 8 6}
Seizures have followed skin use, breathing the vapour and swallowing. A pooled review of 110 reported cases (49 children) found seizures after eucalyptus oil was put on the skin, breathed in or swallowed; breathing the vapour was the commonest route. A case series from India describes ten people with seizures after inhaling the oil, and 17 children had a generalised seizure about 20 minutes (median) after swallowing drops. Most people recovered fully. Many reports involve unlicensed products or mixtures with camphor and menthol, so the share caused by eucalyptus alone is unclear. Systematic review ^{37 29 41 30 7}
Asthma and airway irritation: take care, and never swap it for asthma medicine. Breathing in strong eucalyptus vapour can irritate the airways in some people. One woman had vocal cord dysfunction (the cords closing during breathing, which can look like asthma) triggered by eucalyptus in a blinded test, and allergy tests were negative, so it looked like irritation. The EU says to see a doctor if breathlessness, fever or pus-coloured phlegm appear. We found no study that measured bronchospasm in people with asthma using eucalyptus oil or steam. The cineole capsule trials in asthma did not report worsening in their abstracts, but capsules are a different product. Case report ^{20 7 53}
Pets: eucalyptus is listed as toxic to cats and dogs. The ASPCA lists eucalyptus as toxic to dogs, cats and horses, names eucalyptol as the toxic principle, and lists salivation, vomiting, diarrhea, depression and weakness. That is a plant listing. We found no study of diffused or skin-applied oil in pets, so keep oils, rubs and diffusers away from animals and ask a vet. Authoritative guidance ¹
Possible interactions with medicines through liver enzymes (unproven in people). In rats, cineole made liver enzymes work harder and shortened the effect of a sleeping drug. In a small 1970 experiment in five volunteers who breathed cineole, blood levels of a test drug fell in four of five. The EU assessor called the method weak and said no conclusion can be drawn, so the EU monograph states 'none reported' for interactions. In the lab, eucalyptus oil weakly blocked a liver enzyme (CYP3A4) instead. One man on warfarin had a fall in his clotting test (INR) while using a lozenge with eucalyptus oil, menthol and liquorice, so eucalyptus cannot be blamed alone. Tell your doctor or pharmacist if you use eucalyptus oil regularly, especially with warfarin or seizure medicines. Animal research ^{8 2 32}
Skin allergy and irritation; pure oil is potent. The EU lists allergic reactions, including severe ones, and contact eczema, with unknown frequency. Its safety database holds 4 serious allergy reports among 49 single-ingredient cases, including an anaphylactic reaction in a child using a bath additive. Companies notified 'may cause an allergic skin reaction' for pure cineole in 84.2% of 2,296 reports. Poison Control says pure essential oils are potent, and we do not advise using the undiluted oil on skin. Do not use it on broken or irritated skin, and keep it away from the eyes. Authoritative guidance ^{7 8 36 39 16}
Pregnancy and breastfeeding: not recommended. The EU says safety in pregnancy and breastfeeding has not been established and use is not recommended. In rats cineole crossed the placenta but not into milk; in nursing women, cineole taken by mouth appeared in breast milk in varying amounts (as quoted in the EU report). These are gaps in data, not proof of harm. Authoritative guidance ^{7 8}
Liver: no clear signal in the sources read. One possible herb-related liver injury case involving Eucalyptus globulus was recorded among 198 liver injury cases in Berlin (product, dose and a co-taken antibiotic unknown; recovered in 30 days). The EU assessor concluded the case does not support a liver-harm signal. Case series ^{5 8}
Oil, cineole capsules and mouth products are different things. Pure oil is strong and risky if swallowed. Isolated cineole capsules are a medicine tested in trials, with mild stomach side effects. Rubs and lozenges are mixtures that may hold camphor or menthol. Safety statements for one do not apply to the others. Authoritative guidance ^{7 25 38}

Side effects 8

Effect	How often	Severity and recovery	Evidence
Poisoning after swallowing (drowsiness, vomiting, unsteadiness, coma, breathing problems, seizures) Frequency cannot be given: reports come from hospital and poison-centre series. In one Melbourne series 59% of 109 children had effects; in a Queensland series 80% of 41 had none.	Not established	mild to life-threatening Most children and adults recovered; a few deaths are reported	Case series ^{49 51 10 21 45 8 13}
Seizures Occurred after skin use, inhaling and swallowing; many products were mixtures or adulterated.	Not established	serious Most recovered without lasting harm in pooled reports; one infant case had later seizures that may have had another cause	Systematic review ^{37 29 41 30 8}
Reflex voice-box spasm and brief stopped breathing in infants and toddlers (laryngospasm) The basis of the EU contraindication under 24 months; described as a risk, not as counted cases.	Not established	potentially serious Not reported in the sources read	Authoritative guidance ^{7 8}
Allergic reactions, including severe ones, and contact eczema Frequency not known. A florist reacted to eucalyptus stem and leaf but not to the 2% oil in patch tests (reported in the EU report), so allergy to the plant and to the oil are not always the same.	Not established	mild to serious Resolves after stopping in the cases described	Authoritative guidance ^{7 8 16}
Stomach upset: heartburn, abdominal pain, nausea, vomiting, diarrhoea In the sinus trial of isolated cineole 2 of 76 had heartburn or rash; the EU assessment report quotes heartburn in 9 of 110 and nausea/diarrhoea/heartburn in 3 of 110 in a 6-month cineole trial. These figures are for cineole capsules, not oil or tea.	Not established	mild Yes	Controlled trial ^{25 15 7}
Skin or eye irritation from rubs More irritant side effects with a vapor rub than with petrolatum or no treatment in children aged 2 to 11 (the abstract gives no counts). Wash hands before touching the eyes.	Not established	mild Yes	Controlled trial ^{38 7}
Voice-box irritation (vocal cord dysfunction) from inhaled eucalyptus One well-documented case; can mimic asthma.	Not established	moderate Not described	Case report ^{20 8}
Burns from hot-water steam inhalation The EU warns of burns from inhaling over hot water and says to keep the eyes out of the steam.	Not established	mild to moderate Not stated	Authoritative guidance ⁷

Liver

No clear case of liver damage from eucalyptus oil or cineole capsules was found. Among 198 liver injury cases in Berlin hospitals, one was rated 'possible' for Eucalyptus globulus (the product, dose and a co-taken antibiotic were not documented; liver tests normalised within 30 days after stopping; no liver failure). The EU assessor judged the case does not support a liver-harm signal. Animal toxicity studies mention liver changes only at very high doses. ^{5 8}

How often. Not known. A single possible case is not a rate.

Monitoring. No routine liver blood tests are recommended in the EU documents read. Tell your doctor if you have liver disease; German monographs cited by the EU report advise against oral use in severe liver disease.

Douros 2016, Berlin Case-Control Surveillance Study. One possible case of liver injury among 198; ALT 6.1 times the upper limit of normal; recovered in 30 days; causality 'possible' only. ⁵

This is a safety connection. It is not evidence that Eucalyptus Oil supports liver health.

Medicines and supplements 9

With	Why it matters	Importance	Evidence	What to do
Medicines, in general drug	Not specific to eucalyptus	Poison Control says essential oils may interact with medications.	Authoritative guidance Not enough evidence ³⁹	Ask a pharmacist.
Medicines cleared by liver enzymes (general); the best-studied example is aminopyrine, an old test drug drug	Cineole may induce liver enzymes (CYP) that break down medicines	Rat studies (Jori 1969/1972, Madyastha 1986) show liver enzyme induction after cineole by injection or inhalation. A 1970 volunteer study (5 people) found aminopyrine clearance rose in 4 of 5 after 10 days of inhaled cineole. The EU assessor said the method was not state of the art (one-point measurement) and no conclusion can be drawn.	Animal research Not enough evidence ⁸	Possible, not proven. Tell your pharmacist if you use eucalyptus oil regularly. Avoid regular use alongside medicines with a narrow safety margin unless your doctor agrees.
Medicines that depend on the liver enzyme CYP3A4 drug	Lab tests show eucalyptus oil weakly blocks CYP3A4 and that 1,8-cineole is itself broken down by CYP3A4/3A5 in human liver	Weak blocking at high lab concentrations compared with levels in people; the EU assessor judged the clinical relevance unclear. This points the opposite way to the induction findings, so net effect cannot be predicted.	Laboratory research Not enough evidence ⁸	No action beyond telling your pharmacist.
Warfarin drug	Unknown; a lozenge containing eucalyptus oil, menthol and liquorice was used	One 67-year-old man's INR fell below target during about a month of the lozenges and stabilised after stopping. The lozenge has several ingredients (liquorice also affects some drugs) and warfarin is cleared mostly by CYP2C9; cause not proven.	Case report Very low certainty ^{2 8}	If you take warfarin, tell your clinic before using eucalyptus products regularly.
Seizure medicines and drugs that lower the seizure threshold drug	Eucalyptus oil can trigger seizures; cineole may also change drug levels	No interaction study was read. The EU contraindicates the oil in children with a history of seizures.	Pharmacological theory Not enough evidence ^{7 37}	If you or your child have a seizure disorder, avoid eucalyptus oil and ask your doctor.
Sedatives and other depressants of the nervous system drug	Swallowed oil causes drowsiness; rat data show eucalyptus oil changes sleeping-drug effects	Not studied in people at normal use.	Animal research Not enough evidence ^{8 49}	Do not combine swallowed oil with sedatives.
Other skin creams and medicines applied on the same skin drug	Cineole increased skin absorption of a cancer drug through rat skin in a lab test	Rat study quoted in the EU report; no human data.	Animal research Not enough evidence ⁸	Do not apply eucalyptus oil over medicated patches or creams without asking a pharmacist.
Herbs and supplements herb		The EU monograph states interactions 'none reported' for the oil.	Authoritative guidance Not enough evidence ⁷	Tell your pharmacist about all herbs and supplements.
Food and alcohol food	No data	No data in the sources read.	Authoritative guidance Not enough evidence ⁷	No specific advice.

Who should check first 9

Situation	Advice	Evidence
Allergy to eucalyptus oil or 1,8-cineole	Do not use. EU contraindication.	Authoritative guidance ⁷
Children under 24 months	Do not use. Risk of laryngospasm (EU). Never put on or near the face.	Authoritative guidance ^{7 8}
Children with a history of seizures (febrile or not)	Do not use the oil (EU contraindication). Eucalyptus oil is a documented seizure trigger.	Authoritative guidance ^{7 37}
Pregnancy and breastfeeding	Not recommended (EU): safety not established. Ask your doctor or midwife.	Authoritative guidance ⁷
Broken or irritated skin; large skin injuries or open wounds	Do not apply oil. The EU contraindicates full hot baths with large skin injuries, open wounds, acute skin disease, high fever, severe infection, severe circulatory disturbance or heart failure.	Authoritative guidance ⁷
Asthma or other lung disease	Not a replacement for prescribed medicine. Stop and seek advice if breathing gets worse; see a doctor for breathlessness, fever or pus-coloured phlegm (EU).	Authoritative guidance ^{7 20}
Inflamed or ulcerated stomach and gut, gall bladder disease, severe liver disease (oral use)	Use oral oil with caution or avoid (EU: caution in inflamed and ulcerated gut conditions; German monographs cited by the EU list gut, bile duct and severe liver disease as reasons not to use it).	Authoritative guidance ^{7 8}
Before surgery	No data on surgical risk in the sources read; tell your anaesthetist if you take it regularly because of possible liver-enzyme effects.	Pharmacological theory ⁸
Pets in the home (cats, dogs, horses)	Keep oils, rubs and diffusers away from animals; the ASPCA lists eucalyptus as toxic to them. Ask a vet.	Authoritative guidance ¹

Overdose, product quality and regulators

Summary. Pure eucalyptus oil is toxic if swallowed, especially by small children. Animal and cell tests of oil safety are limited: the EU says adequate tests of genotoxicity, carcinogenicity and reproductive toxicity have not been performed.

Animal. Rat studies at high cineole doses showed liver enzyme induction; some oil tests in mice showed no harm to the fetus at one dose. A fungal assay hinted at genotoxicity of one oil sample, so tests in mammal cells were called for by the EU assessor.

Human doses studied. Isolated cineole capsules were studied for up to 6 months in trials of asthma and COPD, with side effects similar to placebo in the COPD trial. Inhaled oil was studied for 3 days and 1 month. No dose advice is given here.

High dose or long term signals. In reports of children, small swallowed amounts have caused drowsiness; adults have survived large swallowed amounts with intensive care, and deaths are described. Frequent daily use for 20 years of a camphor-menthol-eucalyptus nasal product was linked to lipoid pneumonia in one case report (reported in the EU report).

Overdose response. EU oil monograph: swallowing more than recommended can cause abdominal pain, vomiting, diarrhoea, nausea, breathing problems, depression of the nervous system, loss of consciousness, convulsions, unsteadiness and constricted pupils. Skin overdose causes irritation. Call a poison centre or emergency service.

Genotoxicity. No guideline-conform tests of eucalyptus oil are available (EU). Cineole was not mutagenic in a bacterial test at one dose; the EU monographs state that adequate tests of genotoxicity, carcinogenicity and reproductive toxicity have not been performed.

Toxic or hazardous parts. The concentrated essential oil is the toxic form. We found no source describing toxic seeds or bark of E. globulus for medicinal use.

Product quality is a real issue. Reports of poisoning in India involved unlicensed 'eucalyptus oil' that contained camphor, apparently made from the cineole fraction of camphor laurel. The European Pharmacopoeia oil specification quoted in the EU report allows at most 0.1% camphor and requires at least 70% 1,8-cineole. Poison Control says essential oils are not well regulated, so species, strength and contaminants can be hard to know.

Camphor in 'eucalyptus oil'. Two adult poisoning cases in India involved a product in which camphor was detected; the EU assessor called this possible 'fake eucalyptus oil' and noted seizure reports often involve mixtures with camphor and menthol. ^{21 8}

Different eucalyptus species. Eucalyptus oils differ in cineole content by species. E. globulus, E. polybractea and E. smithii are covered by the EU monograph; E. radiata is a separate accepted species also sold as eucalyptus oil, and lemon eucalyptus (Corymbia citriodora, a repellent plant) is a different product again. Results for one do not carry over to the others. ^{7 8 11}

Pesticides, heavy metals and residues. No survey of eucalyptus oil products was found in the sources read. ⁸

Body	Action	Date
European Medicines Agency, HMPC (oil) (European Union)	EU herbal monograph (traditional use) on eucalyptus oil (E. globulus, E. polybractea, E. smithii): cough with a cold; localised muscle pain. Final, Revision 1. source	2024-11-20
European Medicines Agency, HMPC (oil assessment report) (European Union)	Assessment report supporting the oil monograph; no clinical studies of the oil; cineole trials considered supportive. source	2024-11-20
European Medicines Agency, HMPC (public summary) (European Union)	Public summary of the oil conclusions: traditional use for cough with a cold and localised muscle pain; not for children with a history of seizures; older limit under 30 months (the 2024 monograph says 24). source	2016-12-05
ASPCA Animal Poison Control Center (United States)	Lists eucalyptus as toxic to dogs, cats and horses; names eucalyptol; lists salivation, vomiting, diarrhea, depression, weakness. source	n/a
Poison Control (US National Capital Poison Center) (United States)	Says swallowed eucalyptus oil can cause seizures; essential oils are potent; keep bottles locked away from children and pets. source	n/a

When to get medical help

A child, pet or anyone has swallowed eucalyptus oil, a rub or vaporiser liquid: call your poison centre or emergency number right away, even if they seem fine. Do not make them vomit. US Poison Help is 1-800-222-1222.
A seizure, fits, unusual sleepiness, being hard to wake, unsteady walking, or confusion after any use.
A baby or young child stops breathing for a moment, gasps, goes blue, or has noisy breathing after oil or rub was used near the face.
Swelling of the face, lips or throat, wheeze, trouble breathing, or widespread hives (severe allergy).
Breathing gets worse during or after breathing the vapour, or the voice box seems to tighten.
Cough with fever, breathlessness or pus-coloured phlegm, or cough or cold symptoms lasting more than a week (EU advice).
Skin that becomes red, blistered or swollen after using the oil: stop and wash it off.

Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.

General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.

Frequently asked questions

Is eucalyptus oil safe to swallow?

No. We do not advise swallowing it. A Melbourne series found 59% of 109 young children who swallowed it had symptoms, from drowsiness to unconsciousness, adults have had seizures after swallowing it, and one man died. If a child or pet may have swallowed any essential oil, call poison control (US: 1-800-222-1222) or your emergency number and do not make them vomit.

^{49 45 13 39}

Can eucalyptus oil cause seizures?

Yes, there are many reports. A pooled review of 110 cases (49 children) found seizures after skin use, breathing the vapour and swallowing, with inhaling the commonest route. Most people recovered. The EU says the oil must not be used by children with a history of seizures.

^{37 29 41 7}

Is eucalyptus oil safe for babies and children?

The EU says not under 24 months, because it can cause a reflex spasm of the voice box. Never put the oil or a rub on or near the face of a baby or small child. Ask a paediatric clinician before using it on any child, and keep bottles out of reach.

^{7 8 4}

Is eucalyptus oil safe for cats and dogs?

No. The ASPCA lists eucalyptus as toxic to dogs, cats and horses, with drooling, vomiting, diarrhea, depression and weakness. We found no study of diffused oil in pets, so keep oils, rubs and diffusers away from animals and ask a vet.

Can eucalyptus oil trigger asthma?

It can irritate the airways in some people. One woman had vocal cord tightening, which can look like asthma, when she breathed eucalyptus. We found no study measuring asthma attacks with the oil. Do not use it in place of prescribed asthma medicine, and stop if breathing gets worse.

^{20 7}

Does eucalyptus oil help a cold, sinus infection or cough?

The EU accepts it for cough with a cold on long use, but no trial of the oil itself was found. The positive trials are of cineole capsules, a medicine, for sinus infection, bronchitis, asthma and COPD, mostly from one research group.

^{8 25 17 9}

What is the difference between eucalyptus oil and cineole capsules?

Cineole is the main compound in the oil. The capsules hold only cineole and are made as a medicine; most of the good trials used them. The bottled oil holds other compounds and is dangerous if swallowed. Results for the capsule do not carry over to the oil.

^{52 23 8}

Is eucalyptus oil safe in pregnancy or breastfeeding?

The EU says safety has not been established and does not recommend it. Cineole crossed the placenta in rats and was found in breast milk in some women who took it by mouth. Ask your midwife or doctor.

^{7 8}

Does eucalyptus oil interact with medicines?

The EU reports none, but animal work suggests cineole may speed up liver enzymes, and one man on warfarin had a fall in his clotting test while using a lozenge with eucalyptus oil, menthol and liquorice. Tell your pharmacist if you use it regularly, especially with warfarin or seizure medicines.

^{8 2 32}

Can eucalyptus oil cause an allergic reaction?

Yes. The EU lists allergic reactions, including severe ones, and contact eczema, with unknown frequency. Its safety database includes an anaphylactic reaction in a child using a bath additive. Stop and wash the oil off if a rash appears.

^{7 8}

Does eucalyptus oil help with pain?

Two small trials of breathing the oil found lower pain scores after knee surgery and in rheumatoid arthritis, but the smell is hard to hide and the effects are uncertain. For rubbing it on sore muscles the EU accepts it only on long use, with no trial of the oil found.

^{24 50 8}

What does the European Medicines Agency say about eucalyptus oil?

It accepts eucalyptus oil medicines for cough with a cold and localised muscle pain on long-standing use, not trials. It says do not use under 24 months or in children with a history of seizures, and that people with large skin injuries, open wounds, high fever, severe infections or heart failure should not take full hot baths with it.

^{7 6}

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Editorial transparency

Written by: AlternativeMed editorial team. Research compiled with AI assistance, then checked against PubMed records.
Medical review: None. This page has not been reviewed by a physician or pharmacist.
First published: 2026-10-25
Last substantive update: 2026-10-25
How we research: We checked every PubMed paper against its PubMed record and read its abstract, and read the EMA, Poison Control and ASPCA pages. The EMA documents were read as text extracted by software. We checked the plant names in GBIF and the main compound in PubChem. We did not find or read a LiverTox, LactMed, FDA or NCCIH statement.
How we rate evidence: See "How we rate evidence" in the Evidence tab.
Independence: No product is promoted on this page. No affiliate links are shown. Trials paid for by the maker of a cineole capsule are labelled.

Sources 55

Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.

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Where to buy

Check the label first. Whatever you buy, look for these:

The botanical (Latin) name on the label and 100% pure oil
A dark glass bottle and a batch number
Essential oils are strong: dilute for skin, and do not swallow unless a qualified professional directs it
Keep away from children and pets

Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.

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Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.