Lemon-scented gum (Corymbia citriodora); the oil comes from the leaves.

Essential Oils & Aromatherapy · Essential oil

Lemon Eucalyptus Oil (and PMD)

Q: Is lemon eucalyptus oil the same as PMD or an 'oil of lemon eucalyptus' repellent?

No. The oil is distilled from the leaves. PMD is the repellent compound that industry makes from a compound in the oil. The EPA says oil of lemon eucalyptus contains PMD but is regulated as a separate pesticide chemical. A registered repellent has a registration number on its label; a bottle of essential oil does not.

Q: Does it repel mosquitoes as well as DEET?

PMD sprays protected about as well as DEET in a 100-person placebo-controlled trial in Senegal (a non-significant trend favoured DEET 50% over PMD 20%). In Queensland a lemon eucalyptus oil product gave over 95% protection for 3 hours against 7 hours for 40% DEET. Reviews say plant-based repellents usually last two to four hours against five to nine for DEET. Times vary by product.

Q: Is it safe for babies and young children?

The CDC says not to use products containing OLE or PMD on children under 3 years old. The EPA says some OLE labels carry the warning and certain products with OLE alone at 30% or less do not. Follow the label and ask a paediatrician. We found no source that makes bottled essential oil safe for babies.

Q: Can I swallow it or use it undiluted on skin?

No. We do not advise swallowing essential oils. Poison Control says swallowed eucalyptus oil can cause seizures, pure oils are potent and should be diluted in a carrier oil, and they should not go on damaged skin. If anyone may have swallowed some, call Poison Help at 1-800-222-1222 (US) or your emergency number.

Q: Is it safe for cats and dogs?

Not shown to be safe. Pet Poison Helpline says concentrated eucalyptus essential oil by mouth or on skin can cause severe signs in pets, and the ASPCA lists eucalyptus as toxic to dogs, cats and horses. Those pages are about eucalyptus in general. Keep oils, repellents and diffusers away from pets and ask a vet.

Q: Is it safe in pregnancy or while breastfeeding?

The CDC says EPA-registered repellents, including those with OLE or PMD, are proven safe and effective when used as directed, even for pregnant and breastfeeding women. That covers registered products. We found no source on the bottled oil in pregnancy or breastfeeding. Ask a doctor or midwife.

Q: Can it cause a rash or allergy?

Yes, it can. Poison Control says rash is the most common allergic reaction to essential oils. A Cochrane review of topical repellents in general found mild skin reactions in 0.6% of users. A compound in the oil, citronellol, caused patch-test allergy in a small share of dermatitis patients, more when oxidised. Wash off and stop if a rash appears.

Q: Does it repel ticks?

An open trial of a refined lemon eucalyptus extract spray in 111 Swedish adults found fewer attached ticks reported (42 versus 112), but there was no placebo and ticks were counted from diaries. Evidence is low. A repellent does not replace checking for ticks.

Q: Does it prevent malaria or dengue?

Not shown. A Cochrane review found topical repellents in general may slightly reduce malaria, with low-certainty evidence, and its abstract does not name lemon eucalyptus or PMD. Ask a travel clinic about proper protection.

Q: Is lemon eucalyptus the same as ordinary eucalyptus oil?

No. They come from different trees and the oils differ. The ASPCA names eucalyptol as the toxic principle of eucalyptus, and eucalyptol was one of several main compounds in a lemon eucalyptus oil analysis, but citronellal was the largest. The poisoning reports do not say which species was used, so treat both oils with the same caution.

Corymbia citriodora (older name Eucalyptus citriodora) · also called Oil of lemon eucalyptus (OLE), lemon-scented gum oil, PMD (the refined repellent ingredient)

Lemon eucalyptus oil is a lemon-smelling oil distilled from the leaves of the lemon-scented gum tree. Industry makes a refined repellent ingredient called PMD from one of its compounds, and sprays with PMD or "oil of lemon eucalyptus" are sold as mosquito repellents. In a good field trial PMD sprays protected about as well as DEET, but protection times vary a lot between tests and products. The main caution: the registered repellent and the bottled oil are different products, the CDC says not to use OLE or PMD products on children under 3, and bottled oil should never be swallowed.

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

About Lemon Eucalyptus Oil (and PMD)

Lemon eucalyptus oil and PMD are two things people mix up. The oil is the distilled leaf oil; PMD is a refined repellent made from it. Regulators recommend registered repellents, not the bottled oil. PMD protects against mosquito bites, but times vary by product, and we found no proof either prevents disease. Safety comes first: not for children under 3 (CDC), no swallowing, rash and allergy are possible, and pets are at risk.

What lemon eucalyptus oil and PMD are

The tree is Corymbia citriodora, in the myrtle family (Myrtaceae). GBIF lists Eucalyptus citriodora as an older name for the same tree. The oil is distilled from its leaves.

In one lab analysis of oil from Egyptian trees, citronellal was 56%, followed by citronellol (14.7%) and citronellol acetate (12.3%), with isopulegol and eucalyptol among the main others. In another study citronellal was 38% to 48%, depending on how the oil was distilled. So oil makeup varies.

PMD (p-menthane-3,8-diol) is the repellent compound. A 2026 paper says industry makes PMD from citronellal by a chemical step. A 2024 paper calls PMD the main component of lemon eucalyptus oil, while the analyses above list citronellal as the main compound, so the sources disagree on how much PMD the raw oil holds.

Ordinary eucalyptus oil is a different oil from other eucalyptus trees, and citronella oil comes from grasses. See the related pages.

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What the repellent research shows

Refined PMD products have the best evidence. A 100-person, double-blind, placebo-controlled field trial in Senegal found PMD sprays protected about as well as DEET and icaridin sprays for about 8 hours, with a non-significant trend toward more protection from DEET 50% than PMD 20%. Cage tests give shorter and more varied times: 15% PMD protected 0.5 to 1 hour in a Swiss cage test, yet at least 6 hours in the field. One branded long-release PMD product reached 14.2 hours in six people in a cage, in a paper with no funding statement in the abstract and a promotional title.

Lemon eucalyptus oil formulations did less well than DEET. In Queensland a 32% product gave over 95% protection for 3 hours, against 7 hours for 40% DEET. A 2026 review of 19 human studies says natural repellents based on citronella, lemon eucalyptus, neem and lemongrass usually protect for two to four hours, against five to nine hours for DEET. A 2002 test found most botanicals gave under 20 minutes.

Ticks: an open trial of a refined extract spray in 111 Swedish adults found fewer attached ticks, but no placebo was used.

Disease: we found no trial showing lemon eucalyptus oil or PMD prevents any disease.

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Registered repellent, raw oil, and plant-based sprays are different

The EPA says a registration number on a repellent label means the company gave EPA technical information on effectiveness. The CDC recommends EPA-registered products. A bottle of essential oil sold for aromatherapy or home-made sprays has no such number, and we found no placebo-controlled trial of plain diluted lemon eucalyptus essential oil on skin.

The Cochrane abstract on topical repellents does not say which ingredients were tested, so it cannot be used for this oil. Results for one product do not carry over to another: strengths, formulations and mosquito species differ between trials.

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The research in one view

Most repellent studies are small. Many are cage tests in 3 to 15 people. The Senegal trial is the largest well-controlled one. Many abstracts do not state funding or sample size. One 2026 review has a correction notice listed that we did not read.

Nothing on this page proves benefit for anything other than keeping biting insects off the skin. The germ-killing and inflammation results are lab or computer work only. We found no human trial of the oil as a scent for mood, sleep, breathing or pain.

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What regulators say

The CDC lists OLE and PMD among active ingredients of EPA-registered repellents that, used as directed, it calls proven safe and effective, even for pregnant and breastfeeding women. The EPA lists PMD and oil of lemon eucalyptus as separately regulated active ingredients. These statements cover registered products, not bottled essential oil.

We found no LiverTox, LactMed or European Medicines Agency statement for lemon eucalyptus oil or PMD. The CDC mosquito pages refused our request, so only the CDC Travelers' Health page was read.

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At a glance

Traditional uses history, not proof

No traditional-use source was read for this page. The best-documented use is as a mosquito and tick repellent in modern products.

Studied for research

Mosquito bites, refined PMD or registered repellents on the skin, moderate
Mosquito bites, lemon eucalyptus oil formulations, low
Mosquito bites, botanical repellents as a group (older lab test), mixed
Tick bites, a refined extract spray, low
Preventing malaria or dengue, insufficient
Germ and tick killing in the lab, insufficient
Inflammation, computer prediction only, insufficient

Main compounds

Citronellal, the largest compound in the oils analysed
Citronellol, isopulegol and eucalyptol (1,8-cineole)
PMD (p-menthane-3,8-diol), made from citronellal in repellents

Common forms

Essential oil distilled from leaves
Registered repellent sprays and wipes with oil of lemon eucalyptus or PMD
Refined extracts such as Citriodiol (a trade name)
Ordinary eucalyptus oil (a different product)
Citronella oil (a different product)

Research links: CDC Travelers' Health: Avoid bug bites · EPA: Skin-applied repellent ingredients · EPA: Using insect repellents safely · Poison Control: Essential oils · Pet Poison Helpline: Eucalyptus · Senegal PMD field trial (abstract) · Cochrane review: topical repellents and malaria (abstract) · Research Library · Genes & Biomarkers Library

What it is and its history

Accepted scientific name: Corymbia citriodora
Naming authority: (Hook.) K.D.Hill & L.A.S.Johnson
Synonyms: Eucalyptus citriodora Hook.
Common names: Lemon eucalyptus (English); Lemon-scented gum (English); Lemon eucalyptus oil (English); Oil of lemon eucalyptus (OLE) (English); PMD (p-menthane-3,8-diol) (English)
Family or group: Myrtaceae (myrtle family), per GBIF.
Classification: Plantae > Myrtaceae > Corymbia > Corymbia citriodora
Native range: Not checked.
Habitat: Not checked.
What it looks like: Part used: Leaves. The papers read describe oil from C. citriodora leaves, obtained by steam distillation.
Look-alikes and adulterants: Ordinary eucalyptus oil comes from other Eucalyptus species, and the Pet Poison Helpline and ASPCA pages link eucalyptus toxicity to eucalyptol (1,8-cineole). Citronella oil, which also smells lemony, comes from grasses. Do not swap these oils.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
US regulatory (2005)	A 2024 lab paper says the CDC approved two repellents that do not contain DEET in April 2005, including PMD.	Ozokan 2024
Modern repellent manufacture	A 2026 paper says industrial PMD production depends on chemically made citronellal as a starting material.	Zuo 2026

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
Citronellal PubChem 7794	monoterpene aldehyde	Leaf oil 56% in oil from Egyptian trees; 38.24% (steam distillation) to 48.41% (microwave-assisted) in another study.	The largest compound in the oils analysed. Industry uses it to make PMD. ^{32 19 13 23}	Laboratory analysis
Citronellol PubChem 8842	monoterpene alcohol	Leaf oil 14.7% in the Egyptian oil (with citronellol acetate 12.3%).	A fragrance compound that can cause contact allergy, more so when oxidised. ^{32 19 12}	Laboratory analysis and human patch test
Isopulegol PubChem 170833	monoterpene alcohol	Leaf oil Named as a primary constituent in the Egyptian oil; share not stated in the abstract.	Not described in the sources read. ^{32 19}	Laboratory analysis
Eucalyptol (1,8-cineole) PubChem 2758	monoterpene ether	Leaf oil Named among the primary constituents in the Egyptian oil; share not stated in the abstract.	The compound the ASPCA names as the toxic principle of eucalyptus. ^{32 19 29}	Laboratory analysis; regulator statement
p-Menthane-3,8-diol (PMD) PubChem 556998	monoterpene diol	Refined extract or made from citronellal Not given for the raw oil. A 2024 paper calls PMD the main component of lemon eucalyptus oil, while the GC-MS analyses read here list citronellal as the main compound, so the sources disagree.	The mosquito repellent compound in registered OLE and PMD products. ^{32 15 23 19 21}	Human trials (refined products); laboratory

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Mosquito repellency	n/a	The abstracts read do not explain how PMD repels mosquitoes. ²¹	Not established
COX-2, COX-1 and iNOS enzymes (computer docking)	COX-2	Computer models predicted that some compounds in the oil can bind these enzymes. The authors say lab validation is needed. ¹³	Computer model
Bacterial and fungal growth	n/a	The oil slowed bacteria and fungi in dish tests. ¹⁹	Laboratory only

Absorption, metabolism and elimination

Absorption: Not described in any source read.
Distribution: Not established.
Metabolism: Not described.
Elimination: Not established.
Bioavailability: Not established.

Isolated compounds versus whole extracts

Lemon eucalyptus leaf oil, a registered oil-of-lemon-eucalyptus repellent, refined PMD, a branded extract such as Citriodiol, and ordinary eucalyptus oil are different products. PMD is made from citronellal by a chemical step. Almost every human repellent result on this page comes from a refined or branded product, so it does not show what the raw essential oil does. The poisoning reports concern eucalyptus oil in general. Treat each product separately.

Nutritional composition

Lemon eucalyptus oil is not a nutrient and is not a food.

7benefits and uses looked at

32studies and sources checked

Moderate certaintybest evidence rating found

4lab markers tracked in trials

1 moderate certainty1 mixed findings2 low certainty3 not enough evidence

What is Lemon Eucalyptus Oil (and PMD) good for?

The uses people ask about and how strong the evidence is for each. Read the certainty label first. Most human results here come from refined PMD or branded repellents, not from a bottle of essential oil, and they measure bites, not disease.

Mosquito bites (refined PMD or registered 'oil of lemon eucalyptus' repellents on the skin)Moderate certaintyIn a double-blind, placebo-controlled trial of 100 volunteers in Senegal, PMD sprays protected about as well as DEET and icaridin sprays for about 8 hours. A Swiss test of 15% PMD against 15% DEET found at least 6 hours in the field but only 0.5 to 1 hour for PMD in the cage test. Times vary a lot with the product and test. Mosquito bites (lemon eucalyptus oil formulations)Low certaintyIn Queensland a 32% lemon eucalyptus oil formulation gave over 95% protection for 3 hours, against 100% for 7 hours with a 40% DEET formulation. Reviews say plant-oil repellents usually protect for two to four hours. The abstracts do not say whether the oil was raw or refined. Mosquito bites (botanical repellents as a group, 2002 lab test)Mixed findingsA 2002 test in 15 volunteers found most botanical repellents protected for under 20 minutes against over 5 hours for a DEET product. The abstract does not name which botanicals, so it cannot be applied to lemon eucalyptus or PMD. Tick bites (a refined lemon eucalyptus extract spray on the legs)Low certaintyIn an open trial of 111 adults in Sweden, 42 attached ticks were reported in spray weeks and 112 in no-spray weeks. There was no placebo, and ticks were counted from diaries. Preventing malaria, dengue or other diseaseNot enough evidenceNo trial showed that lemon eucalyptus oil or PMD prevents any disease. A Cochrane review of topical repellents in general found they may slightly reduce malaria, with low-certainty evidence. Killing germs and ticks in the labNot enough evidenceThe oil slowed bacteria and fungi in dishes, and PMD killed tick nymphs on a treated surface. This is lab work and does not show an effect on skin or in the body. Inflammation (computer prediction only)Not enough evidenceA 2026 study used computer models to predict that compounds in the oil could bind inflammation-related enzymes. No animals or people were tested.

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.

Mosquito bites: refined PMD or registered 'oil of lemon eucalyptus' repellents on the skin

Moderate certainty

PMD is the repellent ingredient that industry makes from lemon eucalyptus oil. In a double-blind, placebo-controlled field trial of 100 volunteers in Senegal, PMD sprays protected as well as DEET and icaridin sprays compared with placebo, lasting about 8 hours. Other tests give shorter times: in a Swiss cage test PMD 15% protected for 0.5 to 1 hour, while in the field it protected at least 6 hours. So protection depends on the product, the test and the mosquito.

7 studiesNot covered. This page gives no amounts and no way to use a repellent…

Studies, doses and limits

What the trials found

One double-blind, randomised, placebo-controlled cross-over field trial in 100 volunteers in Senegal. One Swiss comparison of 15% PMD with 15% DEET in the lab and the field. Small arm-in-cage tests in 3 to 10 volunteers. A hand-olfactometer comparison of commercial products. One 6-person cage test of a branded long-release PMD product that reported 14.2 hours.

Results

Senegal: four active sprays (PMD 20% and 50%, icaridin 20%, DEET 50%) gave similar, significant protection versus placebo for 8 hours; a non-significant trend favoured DEET 50% over PMD 20% (P = 0.07). Switzerland: median complete protection at least 6 hours in the field for both PMD and DEET, but only 0.5 to 1 hour for PMD in the cage test. South Africa: PMD towelette and DEET gave 90 to 100% protection up to 5 to 6 hours against Anopheles arabiensis. Olfactometer: PMD products comparable to DEET but for shorter periods. Branded long-release product (possibly industry-linked, 6 people): 14.2 hours.

Effect sizes as reported

Senegal: P = 0.07 DEET 50% vs PMD 20% (not significant). Cage test: PMD 0.5 to 1 h vs DEET 0.5 to 2 h. Branded product: 14.2 h mean in 6 people.

Why this rating

One good-sized double-blind placebo-controlled field trial plus several small tests that agree PMD protects. But times range from 0.5 hours to 14 hours depending on product and method, many tests are small cage tests, and one long-protection result is for a branded product with no stated funding.

Form and dose studied

Not covered. This page gives no amounts and no way to use a repellent. Registered products have directions on the label.

Who was studied

Healthy adult volunteers; one trial in Senegalese villages. Children were not studied in the abstracts read.

Limits

Different strengths, formulations and mosquito species. Cage tests may not match outdoor protection. Protection against bites was measured, not protection against disease. The results are for refined PMD products, not for raw lemon eucalyptus oil.

Why researchers looked

Mosquitoes spread malaria, dengue and other diseases, and some people want an option other than DEET.

Traditional use

No traditional-use source was read for this use.

Proposed mechanism Preliminary mechanism

The abstracts used here do not explain how PMD works against mosquitoes.

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

Not for children under 3 on CDC advice. Registered products carry their own label directions. Keep away from eyes and mouth.

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Mosquito bites: lemon eucalyptus oil formulations on the skin (field trials and reviews)

Low certainty

Field trials of products labelled lemon eucalyptus oil show protection, but for shorter times than DEET. In Queensland, a 32% lemon eucalyptus oil formulation gave over 95% protection for 3 hours, against 7 hours for a 40% DEET formulation. In Ethiopia, lemon eucalyptus oil in coconut oil worked better than neem or rue at some strengths. Reviews say plant-oil repellents usually protect for two to four hours and fade fast because they evaporate.

4 studiesNot covered. This page gives no amounts.

Studies, doses and limits

What the trials found

Two field trials: Queensland, Australia (32% LEO versus 40% DEET) and Gambella, Ethiopia (lemon eucalyptus oil 40% to 75% in coconut oil versus other plant products and DEET). Two reviews (2024 narrative review on Aedes aegypti; 2026 systematic review of 19 human studies).

Results

Queensland: 40% DEET gave 100% protection for 7 hours; 32% LEO gave over 95% protection for 3 hours. Ethiopia: all plant products showed repellency; at 40% strength DEET, lemon eucalyptus and pyrethrum beat rue and neem; at 75% DEET and lemon eucalyptus beat pyrethrum and neem (p < 0.05). The abstract gives no protection percentage for the lemon eucalyptus oil. 2026 review: natural repellents based on citronella, lemon eucalyptus, neem and lemongrass usually protect two to four hours; DEET five to nine hours.

Effect sizes as reported

Queensland: over 95% for 3 h (LEO 32%) versus 100% for 7 h (DEET 40%).

Why this rating

Few trials, with unclear sample sizes in the abstracts, different products, and branded formulations. The abstracts do not say whether the 'oil' was raw or refined, so results should not be carried to a bottle of essential oil.

Form and dose studied

Not covered. This page gives no amounts.

Who was studied

Adult volunteers in field conditions in Australia and Ethiopia.

Limits

The Ethiopian trial used 40% to 75% oil in coconut oil, which is not how consumer products are made. The reviews mix several plant oils. No trial of plain home-diluted lemon eucalyptus essential oil against a placebo was found.

Why researchers looked

People look for plant-based repellents. 'Oil of lemon eucalyptus' is the plant-based ingredient the CDC lists among its recommended skin repellents.

Traditional use

No traditional-use source was read for this use.

Proposed mechanism Preliminary mechanism

A 2024 review says the effect of lemon eucalyptus oil fades quickly because the oil evaporates fast. This is the reviewers' explanation, not tested in the trials read.

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

Raw essential oil is not the same as a registered repellent. Do not use undiluted. Not for children under 3 on CDC advice for OLE/PMD products.

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Mosquito bites: botanical repellents as a group (older lab test)

Mixed findings

A 2002 laboratory test in 15 volunteers found DEET products protected longest. All botanical repellents tested except a soybean-oil product protected for less than 20 minutes on average. The abstract does not say which botanicals were tested, so it cannot be used for lemon eucalyptus oil or PMD specifically.

1 studiesNot covered.

Studies, doses and limits

What the trials found

One controlled laboratory comparison with 15 volunteers.

Results

23.8% DEET: mean complete protection 301.5 minutes. Soybean-oil product: 94.6 minutes. IR3535 product: 22.9 minutes. All other botanical repellents: under 20 minutes. Wristbands: no protection.

Effect sizes as reported

301.5 min (DEET) versus 94.6 min (soybean oil) versus under 20 min (other botanicals).

Why this rating

This old result disagrees with later field results for PMD and lemon eucalyptus products, and it does not name the botanicals tested.

Form and dose studied

Not covered.

Who was studied

15 volunteers in a laboratory.

Limits

2002 products. The abstract does not identify lemon eucalyptus or PMD products.

Why researchers looked

To see which repellents sold in the US give reliable and long protection.

Traditional use

Not applicable.

Proposed mechanism Preliminary mechanism

Not tested.

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

Plant-based does not mean lasting. Re-check the product label rather than assuming.

⁵

Tick bites: a refined lemon eucalyptus extract (Citriodiol) spray on the legs

Low certainty

In Sweden, 111 outdoor-active adults used a Citriodiol spray on their lower legs for 2 weeks and no repellent for 2 weeks, in swapped order. They reported 42 attached ticks in spray weeks and 112 in no-spray weeks. Nobody was blinded, and ticks were counted from diaries.

2 studiesNot covered. This page gives no amounts.

Studies, doses and limits

What the trials found

One randomised open cross-over field trial in 111 adults in two Swedish tick areas.

Results

Median attached ticks per person fell from 1.5 to 0.5 (P < 0.05). Ticks below the waist were 13 of 42 (31%) with spray and 73 of 112 (65%) without (P < 0.001). No clear shift of ticks to unprotected body areas was seen.

Effect sizes as reported

42 versus 112 attached ticks.

Why this rating

One trial, not blinded, no placebo, self-reported tick counts, legs only. It tested a refined extract, not the essential oil.

Form and dose studied

Not covered. This page gives no amounts.

Who was studied

Healthy adults in tick areas of Sweden.

Limits

Open study, diary data, one product. It counts ticks, not infections.

Why researchers looked

Ticks spread Lyme disease and tick-borne encephalitis.

Traditional use

No traditional-use source was read for this use.

Proposed mechanism Preliminary mechanism

A lab test found PMD was toxic to tick nymphs on contact for about 24 hours. That is lab work on a treated surface, not shown on people.

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

Tick-borne illness needs medical advice; a repellent does not replace checking for ticks.

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Preventing malaria, dengue or other disease

Not enough evidence

We found no trial showing that lemon eucalyptus oil or PMD prevents any disease. A Cochrane review of topical repellents in general (abstract does not name the ingredients) found that they may slightly reduce malaria, with low-certainty evidence, and that the evidence is not enough where other protection is in place.

1 studiesNot covered.

Studies, doses and limits

What the trials found

A Cochrane review of 8 trials (6 in the meta-analysis); none is identified as testing lemon eucalyptus or PMD in the abstract.

Results

Pooled incidence rate ratio 0.74 (95% CI 0.56 to 0.98) for malaria infection and clinical cases together; separate analyses were not significant. Adverse events 0.6%, mild skin reactions.

Effect sizes as reported

IRR 0.74 (0.56 to 0.98), low certainty.

Why this rating

Low-certainty evidence for repellents in general and none specific to this ingredient.

Form and dose studied

Not covered.

Who was studied

Mostly high-risk groups such as refugees.

Limits

The review does not say which ingredients were used.

Why researchers looked

The reason people use repellents is to avoid mosquito-borne disease.

Traditional use

Not applicable.

Proposed mechanism Preliminary mechanism

Not applicable. Fewer bites are the assumed route.

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

Do not rely on any repellent alone in a malaria or dengue area. Ask a travel clinic.

⁷

Killing germs and ticks in the lab

Not enough evidence

In dishes, oil from Egyptian lemon-scented gum trees slowed bacteria and fungi, and PMD killed tick nymphs on a treated surface. These are lab results and do not show any effect on skin or in the body.

2 studiesNot covered.

Studies, doses and limits

What the trials found

None. Dish and bioassay tests only.

Results

MIC values of 0.06 to 0.20 mg/mL against bacteria and 0.11 to 0.52 mg/mL against fungi in one oil; PMD LC50 0.035-0.037 mg per square cm against tick nymphs at 4 hours.

Effect sizes as reported

Lab MIC and LC50 only.

Why this rating

Lab only. No animal or human data.

Form and dose studied

Not covered.

Who was studied

Not applicable.

Limits

Test-tube and bioassay work. One batch of oil.

Why researchers looked

Researchers look for plant-based germ and pest killers.

Traditional use

Not applicable.

Proposed mechanism Preliminary mechanism

Not tested in the abstracts read.

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

A lab result is not a use. Do not treat skin with the oil because of it.

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Inflammation (computer prediction only)

Not enough evidence

A 2026 study analysed the oil and used computer models to predict that some of its compounds could bind inflammation-related proteins. No animals or people were tested.

1 studiesNot covered.

Studies, doses and limits

What the trials found

None.

Results

Compounds were predicted to bind the enzymes; citronellal share was 38.24% (steam distillation) and 48.41% (microwave-assisted).

Effect sizes as reported

None.

Why this rating

Computer modelling only.

Form and dose studied

Not covered.

Who was studied

Not applicable.

Limits

No lab, animal or human test.

Why researchers looked

Researchers screen plant compounds as possible anti-inflammatory leads.

Traditional use

Not applicable.

Proposed mechanism Preliminary mechanism

Computer docking to COX-2, COX-1 and iNOS. The authors say lab validation is still needed.

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

A computer prediction is not a treatment.

¹³

Connections to the rest of health

How Lemon Eucalyptus Oil (and PMD) 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	Evidence status	Context	Studies
Insect Protection	Moderate certainty	Mosquito bites: refined PMD or registered 'oil of lemon eucalyptus' repellents on the skin: PMD is the repellent ingredient that industry makes from lemon eucalyptus oil. In a double-blind, placebo-controlled field trial of 100 volunteers in Senegal, PMD sprays protected as well as DEET and icaridin sprays compared with placebo, lasting about 8 hours. Other tests give shorter times: in a Swiss cage test PMD 15% protected for 0.5 to 1 hour, while in the field it protected at least 6 hours. So protection depends on the product, the test and the mosquito. Mosquito bites: lemon eucalyptus oil formulations on the skin (field trials and reviews): Field trials of products labelled lemon eucalyptus oil show protection, but for shorter times than DEET. In Queensland, a 32% lemon eucalyptus oil formulation gave over 95% protection for 3 hours, against 7 hours for a 40% DEET formulation. In Ethiopia, lemon eucalyptus oil in coconut oil worked better than neem or rue at some strengths. Reviews say plant-oil repellents usually protect for two to four hours and fade fast because they evaporate.	^{21 2 9 10 17 1 4 6 11 14 5 8 3}
Insect Protection	Not enough evidence	Preventing malaria, dengue or other disease: We found no trial showing that lemon eucalyptus oil or PMD prevents any disease. A Cochrane review of topical repellents in general (abstract does not name the ingredients) found that they may slightly reduce malaria, with low-certainty evidence, and that the evidence is not enough where other protection is in place.	⁷
Insect Protection	Not enough evidence	Killing germs and ticks in the lab: In dishes, oil from Egyptian lemon-scented gum trees slowed bacteria and fungi, and PMD killed tick nymphs on a treated surface. These are lab results and do not show any effect on skin or in the body.	^{19 3}

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Skin	Adverse effect or risk	Documented	Rash and allergy; not for children under 3 (OLE/PMD products, CDC). Preparation or compound: Lemon eucalyptus oil, citronellol and repellent products	^{25 7 12 24}
Integumentary System	Biological association	Moderate certainty	Studied for: Mosquito bites: refined PMD or registered 'oil of lemon eucalyptus' repellents on the skin Studied for: Mosquito bites: lemon eucalyptus oil formulations on the skin (field trials and reviews)	^{21 2 9 10 17 1 4 6 11 14 5 8 3 19}
Immune System	Biological association	Not enough evidence	Studied for: Preventing malaria, dengue or other disease Studied for: Inflammation (computer prediction only)	^{7 13}

E. Health conditions

Connected to	Kind of connection	Evidence status	Context	Studies
Allergic contact dermatitis		Mixed findings	Patch-test study; not the oil itself. Preparation or compound: Citronellol (a compound in the oil), oxidised	¹²

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
Complete protection time (CPT)	Biological association	Moderate certainty	Measured in trials: increase. A lab change is not the same as a health benefit.	^{2 6 5 9}
Bites or landings on treated skin	Biological association	Moderate certainty	Measured in trials: decrease. A lab change is not the same as a health benefit.	^{21 10}
Attached ticks found on the body	Biological association	Low certainty	Measured in trials: decrease. A lab change is not the same as a health benefit.	⁸
Malaria infection and clinical cases	Biological association	Not enough evidence	Measured in trials: decrease. A lab change is not the same as a health benefit.	⁷

J. Genes, receptors and enzymes

Connected to	Kind of connection	Evidence status	Context	Studies
COX-2 and iNOS	Preliminary mechanism	Computer model	Computer-predicted binding only.	¹³

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Citronellal	Biological association	Laboratory analysis	The largest compound in the oils analysed. Industry uses it to make PMD. Preparation or compound: Leaf oil	^{32 19 13 23}
Citronellol	Biological association	Laboratory analysis and human patch test	A fragrance compound that can cause contact allergy, more so when oxidised. Preparation or compound: Leaf oil	^{32 19 12}
Isopulegol	Biological association	Laboratory analysis	Not described in the sources read. Preparation or compound: Leaf oil	^{32 19}
Eucalyptol (1,8-cineole)	Biological association	Laboratory analysis; regulator statement	The compound the ASPCA names as the toxic principle of eucalyptus. Preparation or compound: Leaf oil	^{32 19 29}
p-Menthane-3,8-diol (PMD)	Biological association	Human trials (refined products); laboratory	The mosquito repellent compound in registered OLE and PMD products. Preparation or compound: Refined extract or made from citronellal	^{32 15 23 19 21}

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).

The evidence

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

Evidence by outcome

Mosquito bites: refined PMD or registered 'oil of lemon eucalyptus' repellents on the skin 7 studies Moderate certainty Mosquito bites: lemon eucalyptus oil formulations on the skin (field trials and reviews) 4 studies Low certainty Mosquito bites: botanical repellents as a group (older lab test) 1 studies Mixed findings Tick bites: a refined lemon eucalyptus extract (Citriodiol) spray on the legs 2 studies Low certainty Preventing malaria, dengue or other disease 1 studies Not enough evidence Killing germs and ticks in the lab 2 studies Not enough evidence Inflammation (computer prediction only) 1 studies Not enough evidence

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 read the abstracts of 23 PubMed papers and the CDC Travelers' Health, EPA, Poison Control, Pet Poison Helpline and ASPCA pages, and checked the tree name in GBIF and the compounds in PubChem. We could not read the CDC mosquito pages or find LiverTox, LactMed or EMA statements for this oil.

Study library: every study we checked 32

Design Research type Year from Search

Study	Design	People	Product, dose, length	Result
Carroll 2019 A Milestone In Botanical Mosquito Repellents: Novel PMD-Based Formulation Protects More Than Twice As Long As High-Concentration Deet and Other Leading Products Journal of the American Mosquito Control Association · PMID 31647713 · DOI	Laboratory arm in cage study	6 6 subjects	A branded prolonged-release formulation with 40% Citriodiol (25% PMD of the total) Refined PMD, branded product Product-as-tested (study fact) Exposures every 1 to 2 hours up to 15 hours · vs 25% DEET, a 20% PMD ethanol formulation and 3 other marketed repellents	Mean complete protection time for the branded formulation was 14.2 hours, about 2 to 3 times longer than five leading repellents including 25% DEET and a 20% PMD ethanol formulation. Five of six subjects had no landings after 15 hours. Mean CPT 14.2 h versus 2 to 3 times shorter for the comparators. Methods, limits and funding Outcomes: Complete protection time against Aedes aegypti and Culex quinquefasciatus Limitations: Six subjects, one cage test. It tests one named commercial product and the title is promotional in tone. Funding and competing interests are not in the abstract, so treat it as possibly industry-linked. Not a field result. Funding and conflicts: Not stated in the abstract. Product-specific; possibly industry-linked. Read: abstract
Colucci 2018 Evaluation of standard field and laboratory methods to compare protection times of the topical repellents PMD and DEET Scientific Reports · PMID 30135603 · DOI	Crossover comparison of lab (arm in cage) and field tests, Switzerland	Study participants tested in both lab and at two field sites in Switzerland (number not given in the abstract)	15% PMD and 15% DEET on skin Refined PMD 15% of each (study fact) Complete protection time measured in lab and field · vs DEET 15%	In the field, median complete protection time was at least 6 hours for both PMD and DEET. In the arm-in-cage test DEET slightly outperformed PMD. DEET CPTs were 0.5, 2 and 2 hours (Aedes aegypti, Anopheles stephensi, Culex quinquefasciatus); PMD CPTs were 0.5, 1 and 0.5 hours. Field: at least 6 h for both. Lab cage: PMD 0.5 to 1 h, DEET 0.5 to 2 h. Methods, limits and funding Outcomes: Median complete protection time (CPT) in the arm-in-cage test and in the field Limitations: The number of participants is not given in the abstract. The authors say the landing rates suggest the cage test underestimates protection in areas where fewer mosquitoes land. Field mosquito pressure was therefore lower than in the cage. Funding and conflicts: Research support from a non-US government source is listed; details not in the abstract. Read: abstract
Elmhalli 2009 Acaricidal effects of Corymbia citriodora oil containing para-menthane-3,8-diol against nymphs of Ixodes ricinus Experimental & Applied Acarology · PMID 19169833 · DOI	Laboratory contact bioassay lab	Ixodes ricinus tick nymphs in a lab test	PMD in the lemon eucalyptus oil (Corymbia citriodora) Oil containing PMD 0.002 to 0.1 mg PMD per square cm (study facts) Mortality counted during 5 hours and later · vs Concentration series	Mortality rose with concentration and time. LC50 was 0.035-0.037 mg PMD per square cm and LC95 0.095-0.097 at 4 hours. Lethal activity remained for 24 hours but appeared absent after 48 hours. The authors say PMD is toxic to I. ricinus nymphs and may be useful for tick control. LC50 0.035-0.037 mg/cm2 at 4 h. Methods, limits and funding Outcomes: Tick mortality, LC50, LC95 Limitations: Tick nymphs on treated surfaces in a lab, not on people. It does not show protection from tick-borne disease. Funding and conflicts: Not stated in the abstract. Read: abstract
Faridah 2026 Effectiveness of mosquito repellents for human: A systematic review of human-based studies Acta Tropica · PMID 42285396 · DOI	Systematic review (PRISMA 2020), 19 studies n/a	19 Human studies of repellents published 2015 to 2025	Topical, wearable, spatial and treated-clothing repellents Mixed n/a Studies from 2015 to 2025 · vs DEET versus natural repellents	DEET products most often gave the longest protection, often five to nine hours, with no reports of adverse skin reactions. Natural repellents based on citronella, lemon eucalyptus, neem and lemongrass usually gave two to four hours. Microencapsulation and nanoemulsions improved some formulations. Natural repellents commonly two to four hours; DEET often five to nine hours. Methods, limits and funding Outcomes: Complete protection time, repellency rate, safety Limitations: Findings were described in words because the studies were too different to combine. PubMed lists an erratum for this paper, which we did not read. The abstract does not separate lemon eucalyptus from other plant oils. Funding and conflicts: Not stated in the abstract. Read: abstract
Fradin 2002 Comparative efficacy of insect repellents against mosquito bites New England Journal of Medicine · PMID 12097535 · DOI	Controlled laboratory comparison with human volunteers	15 15 volunteers	Seven botanical repellents, four DEET products, an IR3535 product, three wristbands and a moisturiser Mixed botanical products (the abstract does not name them) Per product (not given in the abstract) Controlled laboratory exposures · vs Different products	DEET products protected longest. A 23.8% DEET product had a mean complete protection time of 301.5 minutes. A soybean-oil repellent protected for 94.6 minutes on average. All other botanical repellents protected for less than 20 minutes on average. Wristbands gave no protection. 301.5 min (23.8% DEET) versus under 20 min for most botanicals. Methods, limits and funding Outcomes: Mean complete protection time Limitations: 2002 products; the abstract does not say whether any contained lemon eucalyptus oil or PMD, so it does not show what PMD products do. Funding and conflicts: Not stated in the abstract. Read: abstract
Frances 2014 Comparative laboratory and field evaluation of repellent formulations containing deet and lemon eucalyptus oil against mosquitoes in Queensland, Australia Journal of the American Mosquito Control Association · PMID 24772681 · DOI	Comparative field trial (and lab evaluation), Queensland, Australia	Volunteers at Redcliffe, Queensland, in February 2012 and February 2013 (number not in the abstract)	A formulation with 32% lemon eucalyptus oil (LEO; Mosi-guard) and a formulation with 40% DEET in ethanol (Bushman) Lemon eucalyptus oil product (the abstract does not say whether it is raw or refined) 32% LEO and 40% DEET (study facts) Field exposure periods over two summers · vs 40% DEET	The 40% DEET formulation gave 100% protection for 7 hours. The 32% lemon eucalyptus oil formulation gave more than 95% protection for 3 hours. DEET 40%: 100% for 7 h; LEO 32%: over 95% for 3 h. Methods, limits and funding Outcomes: Percentage protection against mosquitoes over time Limitations: The abstract gives no number of volunteers, no species list and no statistics. The LEO product is a branded formulation. Funding is not stated. Funding and conflicts: Not stated in the abstract. Read: abstract
Gabaldon Figueira 2023 Topical repellents for malaria prevention Cochrane Database of Systematic Reviews · PMID 37602418 · DOI	Systematic review and meta analysis (8 trials, 6 in the meta analysis)	61651 People living in malaria-endemic regions, including refugees and forest goers; repellents not specific to lemon eucalyptus in the abstract	Topical repellents of various kinds (the abstract does not name them) Not specified n/a Searches to January 2023 · vs No repellent or other background measures	Topical repellents may slightly reduce Plasmodium falciparum infection and clinical incidence taken together (incidence rate ratio 0.74, 95% CI 0.56 to 0.98; 3 cluster trials and 1 trial, 61,651 participants; low certainty), but not when infection (IRR 0.76, 0.56 to 1.02) and clinical cases (IRR 0.66, 0.32 to 1.36) were analysed separately. Adverse events were 0.6% (283 of 47,515) and limited to mild skin reactions. The authors conclude there is insufficient evidence that topical repellents prevent malaria where other control measures are in place. IRR 0.74 (95% CI 0.56 to 0.98), low certainty. Methods, limits and funding Outcomes: Malaria infection and clinical incidence, prevalence, adverse events Limitations: The abstract does not say which repellent ingredients were used, so it does not show a result for lemon eucalyptus oil or PMD. Low-certainty evidence, mostly from risk of bias. Funding and conflicts: Research support from non-US government sources is listed; details not in the abstract. Read: abstract
Gardulf 2004 A prospective cross-over field trial shows protection of lemon eucalyptus extract against tick bites Journal of Medical Entomology · PMID 15605645 · DOI	Randomised open cross over field trial, Sweden (tick infested areas)	111 111 healthy, outdoor-active adults in two areas heavily infested with Ixodes ricinus ticks	Citriodiol spray (a lemon eucalyptus extract) on the lower legs Lemon eucalyptus extract (Citriodiol), refined Daily spray for 2 weeks (study fact) 2 weeks with spray, 2 weeks without, order swapped · vs No repellent	Forty-two attached ticks were reported during spray weeks and 112 during no-spray weeks. The median per person fell from 1.5 (range 0-9) to 0.5 (range 0-2; P < 0.05). Ticks below the waist were 13 of 42 (31%) with spray and 73 of 112 (65%) without (P < 0.001). The authors say additional studies are warranted. 42 versus 112 attached ticks; median 1.5 to 0.5 (P < 0.05). Methods, limits and funding Outcomes: Number of attached ticks reported in a daily diary Limitations: People knew when they were using the spray (no placebo), and ticks were self-reported in a diary. Spray was on the lower legs only. Funding is not in the abstract. Funding and conflicts: Not stated in the abstract. Read: abstract
Goodyer 2020 Characterisation of actions of p-menthane-3,8-diol repellent formulations against Aedes aegypti mosquitoes Transactions of the Royal Society of Tropical Medicine and Hygiene · PMID 32542324 · DOI	Arm in cage laboratory study with volunteers	6 volunteers for complete protection time, 10 for effective-dose and half-life estimates	20% DEET, 30% PMD and a 30% PMD-vanillin formulation on skin Refined PMD As tested: 0.8 to 1.6 mg per square cm (study fact) Arm-in-cage exposures · vs 20% DEET	PMD and DEET showed a very similar dose-to-protection-time relationship. The PMD-vanillin formulation gave 1.5 times the protection time of 20% DEET at the highest dose tested, with little difference at lower doses. ED95 was 0.25 mg per square cm for 30% PMD and 0.09 for 20% DEET. Half-lives were 2.23 hours (PMD) and 2.74 hours (DEET). 1.5-fold longer for PMD-vanillin at the highest dose; ED95 higher for PMD than DEET. Methods, limits and funding Outcomes: Complete protection time, 95% effective dose (ED95) and half-life against Aedes aegypti Limitations: Very small, one mosquito species, cage test only. The PMD-vanillin product is a specific formulation. Funding is a non-US government research support entry; details not in the abstract. Funding and conflicts: Not stated in the abstract. Read: abstract
Govere 2000 Efficacy of three insect repellents against the malaria vector Anopheles arabiensis Medical and Veterinary Entomology · PMID 11129710 · DOI	Controlled crossover laboratory test with human volunteers, South Africa	3 3 adult male volunteers aged 30 to 45	Mosiguard towelettes with PMD (quwenling, 0.574 g), 15% DEET lotion, and a coconut/jojoba/rapeseed oil skin care product Refined PMD towelette 0.8 g PMD towelette, 0.5 g DEET, 1.2 g skin-care product (study facts) Exposure to 200 hungry mosquitoes for 1 minute at 1 to 6 hours · vs Untreated arm of each volunteer; DEET; skin-care product	All three products gave complete protection for up to 3 to 4 hours. DEET and PMD gave 90 to 100% protection up to 5 to 6 hours, while the skin-care product fell to 52% at 6 hours. The authors call the results satisfactory for 4 to 5 hours and say field evaluation is justified. 90 to 100% protection to 5 to 6 h for PMD and DEET. Methods, limits and funding Outcomes: Complete protection and percentage protection against Anopheles arabiensis Limitations: Three men only; lab test with a lab mosquito colony; 2000 publication. Funding and conflicts: Not stated in the abstract. Read: abstract
Hadis 2003 Field trials on the repellent activity of four plant products against mainly Mansonia population in western Ethiopia Phytotherapy Research · PMID 12672146 · DOI	Randomised Latin square field trial, Gambella, Ethiopia	Test subjects exposed to mainly Mansonia mosquitoes (number not in the abstract)	Essential oils of lemon eucalyptus (named in the abstract as Eucalyptus maculata citrodion), rue, pyrethrum oleoresin and neem as 40%, 50% and 75% solutions in coconut oil; DEET for comparison Essential oil in coconut oil (species named as in the abstract) 40%, 50%, 75% (study facts) Field exposure sessions · vs DEET	All plant products showed repellency. At 50%, protection was 91.6% (rue), 87.0% (neem), 96.0% (pyrethrum) and 97.9% (DEET); lemon eucalyptus oil was not tried at 50%. At 40%, DEET, lemon eucalyptus and pyrethrum were significantly more effective than rue and neem (p < 0.05). At 75%, DEET and lemon eucalyptus did significantly better than pyrethrum and neem (p < 0.05). p < 0.05 for DEET and lemon eucalyptus over neem and rue at stated strengths. Methods, limits and funding Outcomes: Percentage protection against bites Limitations: No protection figures for lemon eucalyptus oil in the abstract. The oil strengths used (40% to 75% pure oil in coconut oil) are not what commercial repellents contain. Number of subjects not in the abstract. 2003 publication. Funding and conflicts: Not stated in the abstract. Read: abstract
Hagvall 2020 Patch testing with purified and oxidized citronellol Contact Dermatitis · PMID 32638395 · DOI	Patch test study in dermatitis clinic patients, Sweden	658 658 dermatitis patients	Purified and oxidised citronellol (a fragrance compound that is also in lemon eucalyptus oil) in petrolatum Isolated compound 2% to 6% in petrolatum for patch tests Patch tests · vs Purified versus oxidised	Purified citronellol gave positive reactions in 0.15% to 0.31% of patients, oxidised citronellol in 0.61% to 4.5%. Few irritant reactions were seen. Among those reacting to oxidised citronellol, 34% to 50% also reacted to baseline fragrance markers and 75% to 91% to oxidised linalool or limonene. The authors say citronellol is susceptible to autoxidation. 0.15-0.31% (purified) vs 0.61-4.5% (oxidised). Methods, limits and funding Outcomes: Positive allergic patch-test reactions Limitations: Patients with dermatitis, not the general public. The test used citronellol alone, not lemon eucalyptus oil, so it is a read-across for one compound in the oil. Funding and conflicts: Not stated in the abstract. Read: abstract
Koribeche 2026 Extraction, Phytochemical Profiling, and Computational Evaluation of Corymbia citriodora Essential Oil as a COX-2 Inhibitor: Steam vs. Microwave-Assisted Distillation, GC-MS/MS, Docking, DFT, and MD Simulations Pharmaceuticals (Basel) · PMID 42797428 · DOI	Chemical analysis and computer modelling (no animals or people) lab	Oil from C. citriodora, two distillation methods	Essential oil by steam distillation or microwave-assisted steam distillation Leaf essential oil n/a n/a · vs n/a	Sixty-three compounds were identified. Microwave-assisted distillation raised citronellal from 38.24% to 48.41%. A compound named in the paper ranked highest in computer docking at COX-2 and also bound COX-1. The authors say enzyme and cell tests are needed to validate this. Computer docking only. Methods, limits and funding Outcomes: Oil composition; computer-predicted binding to COX-2, COX-1 and iNOS Limitations: Modelling and prediction only. It shows nothing about inflammation in animals or people. Citronellal shares differ between oils (38 to 48% here; 56% in the Egyptian oil), so oil composition varies. Funding and conflicts: Not stated in the abstract. Read: abstract
Noguera-Gahona 2024 Repellents against Aedes aegypti bites: synthetic and natural origins Frontiers in Insect Science · PMID 39911593 · DOI	Narrative review n/a	Not applicable	Synthetic and natural repellents Mixed n/a n/a · vs n/a	The review says natural repellents such as citronella, lemon eucalyptus and clove oils have proven effective against Aedes aegypti, but they evaporate quickly and protect for a limited time. It says combining essential oils with synthetic compounds has been proposed to improve efficacy. Qualitative. Methods, limits and funding Outcomes: Efficacy and safety of repellents against Aedes aegypti Limitations: Narrative review without stated methods in the abstract. 'Proven effective' is the authors' wording. Funding and conflicts: Not stated in the abstract. Read: abstract
Ozokan 2024 Comparison of the cytotoxicity and zebrafish embryo toxicity of insect repellent ingredients: p-Menthane-3,8-diol synthesized by green chemistry from Eucalyptus citriodora and N,N-diethyl-meta-toluamide Drug and Chemical Toxicology · PMID 38738628 · DOI	Laboratory comparison (human skin cells and zebrafish embryos) lab	HaCaT human keratinocyte cells and zebrafish embryos	PMD synthesised from E. citriodora citronellal, versus DEET Isolated PMD n/a 72 hours post-fertilisation · vs DEET	DEET inhibited keratinocyte growth while PMD-exposed cells showed improved viability and proliferation. In zebrafish embryos PMD was less toxic than DEET in development, oxidant-antioxidant status and acetylcholinesterase activity. The authors suggest PMD is less toxic in these models. PMD less toxic than DEET in these models. Methods, limits and funding Outcomes: Cell viability; embryo development and oxidative markers Limitations: Cells and fish embryos only, not people. The authors are promoting a synthesis method. Funding is not stated in the abstract. Funding and conflicts: Not stated in the abstract. Read: abstract
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 Tropical Doctor · PMID 34282989 · DOI	Case series and systematic review of published cases	110 110 cases (49 children) including 5 new children	Eucalyptus oil in over-the-counter products by skin, inhalation or mouth Essential oil n/a n/a · vs n/a	Inhalational use was the most common route; the commonest seizure type was generalised tonic-clonic. Most cases recovered uneventfully. Adults were less likely to have prolonged and multiple seizures, intensive care or mechanical ventilation. 110 pooled cases. Methods, limits and funding Outcomes: Seizure type, treatment, outcome Limitations: Published case reports only. The abstract does not say which eucalyptus species. Funding and conflicts: Not stated in the abstract. Read: abstract
Rodriguez 2015 The Efficacy of Some Commercially Available Insect Repellents for Aedes aegypti and Aedes albopictus Journal of Insect Science · PMID 26443777 · DOI	Comparative laboratory olfactometer test with a human hand as attractant	Aedes mosquitoes in a Y-tube; one human hand as attractant (sample size not in the abstract)	Eight commercial repellents, two fragrances and a vitamin B patch Mixed commercial products, some with PMD Per product label (not given in the abstract) Repellency over time · vs Other products	Repellents with DEET had a prominent repellency effect over longer times. Repellents containing p-menthane-3,8-diol gave comparable results but for shorter time periods. Some DEET-free citronella or geraniol products had no significant repellency effect. The vitamin B patch had no effect. Qualitative: PMD comparable to DEET but shorter. Methods, limits and funding Outcomes: Repellency over time against two Aedes species Limitations: Olfactometer test, not bites on a person. No numbers in the abstract. The products are not named in the abstract. Funding and conflicts: Not stated in the abstract. Read: abstract
Sai Chandar 2021 Eucalyptus Oil-Induced Seizures in Children: A Single-Center Prospective Study Cureus · PMID 33927923 · DOI	Single centre prospective observational study, South India	17 17 children up to 18 years with a seizure and recent eucalyptus oil exposure; median age 3.75 years	Eucalyptus oil drops taken by mouth in water or milk (species not stated in the abstract) Essential oil Varied amounts (not repeated here) Follow-up 6 to 9 months · vs None	All 17 children had generalised tonic-clonic seizures; median onset 20 minutes after exposure (range 10 to 120 minutes). None had a recurrence over 6 to 9 months. The authors call these seizures underrecognised and recommend asking about eucalyptus oil exposure in a child with a first seizure. 17 children; none recurred. Methods, limits and funding Outcomes: Seizure features, onset, recurrence Limitations: Small series, one hospital, oil taken by mouth. Species not stated. Funding and conflicts: Not stated in the abstract. Read: abstract
Salem 2018 Bioactivity of essential oils extracted from Cupressus macrocarpa branchlets and Corymbia citriodora leaves grown in Egypt BMC Complementary and Alternative Medicine · PMID 29357851 · DOI	Laboratory analysis (GC/MS, microbial and antioxidant tests) lab	Oil from Corymbia citriodora leaves grown in Egypt; bacteria and fungi in dishes	Essential oil from C. citriodora leaves Leaf essential oil Concentrations in dish tests (MIC 0.06 to 0.20 mg/mL for bacteria) Dish tests · vs Ketoconazole (antifungal), BHT (antioxidant)	Main compounds were citronellal (56%), citronellol (14.7%), citronellol acetate (12.3%), isopulegol and eucalyptol. Against bacteria, MIC values were 0.06 to 0.20 mg/mL and against fungi 0.11 to 0.52 mg/mL. Against one fungus (P. funiculosum) the MIC and MFC values were lower than ketoconazole's. Antioxidant activity was higher than the positive control but lower than the standard BHT. Lab MIC values only. Methods, limits and funding Outcomes: Minimum inhibitory concentrations against bacteria and fungi; antioxidant tests Limitations: Test-tube work on plant pathogens and microbes. It does not show any effect on skin or in the body. One batch of oil from Egyptian trees. Funding and conflicts: Not stated in the abstract. Read: abstract
Tibballs 1995 Clinical effects and management of eucalyptus oil ingestion in infants and young children Medical Journal of Australia · PMID 7651249 · DOI	Retrospective hospital case review, Melbourne	109 109 children (mean age 23.5 months) admitted 1981 to 1992 with eucalyptus oil poisoning	Swallowed eucalyptus oil (species not stated in the abstract) Essential oil Known or estimated volumes (not repeated here) Hospital stay mean 22 hours · vs None	Clinical effects were seen in 59%. Depression of conscious state occurred in 28%, vomiting in 37%, ataxia in 15% and lung disease in 11%. All patients recovered. Mean hospital stay was 22 hours; 13 patients spent time in intensive care. The author says ingestion caused significant morbidity in infants and young children and that hazardous treatment and overtreatment were common. 59% had effects; all recovered. Methods, limits and funding Outcomes: Clinical effects, complications, stay Limitations: Old hospital series from Australia. The abstract does not name the eucalyptus species; it is not specific to lemon eucalyptus. Funding and conflicts: Not stated in the abstract. Read: abstract
Uzzan 2009 Efficacy of four insect repellents against mosquito bites: a double-blind randomized placebo-controlled field study in Senegal Fundamental & Clinical Pharmacology · PMID 19744033 · DOI	Double blind randomised placebo controlled cross over field trial, Senegal	100 100 healthy male and female volunteers experienced with mosquito capture, two villages	Spray repellents: icaridin 20%, para-menthane-diol (PMD) 20% and 50%, DEET 50%, and placebo Refined PMD (not raw lemon eucalyptus oil) Strengths as tested (study facts, not advice): PMD 20% and 50% One skin application at 3 to 4 pm; exposure 7 pm to midnight on five nights · vs Placebo spray and the other repellents	All four active repellents gave significant and similar protection against placebo, lasting 8 hours. There was a non-significant trend toward more protection from DEET 50% than PMD 20% (P = 0.07). No serious adverse drug reaction was noticed. P = 0.07 for DEET 50% versus PMD 20% (not significant); all four better than placebo. Methods, limits and funding Outcomes: Protection against mosquito bites (landing/bite counts) on the exposed leg Limitations: Healthy adults in two villages, exposed legs only. The abstract gives no bite counts. Funding is not stated in the abstract. Funding and conflicts: Not stated in the abstract. Read: abstract
Waldman 2011 Seizure caused by dermal application of over-the-counter eucalyptus oil head lice preparation Clinical Toxicology · PMID 21867365 · DOI	Case report	1 A healthy 4-year-old girl	Eucalyptus oil head lice preparation on the skin Essential oil product Used as directed on the product (per the abstract) Single event · vs None	Vomiting, lethargy and ataxia were followed by a brief, self-limited tonic-clonic seizure. Recovery occurred rapidly after the skin was washed. One child. Methods, limits and funding Outcomes: Seizure and recovery Limitations: Single case. It shows skin exposure can cause toxicity, but not how often. Species not stated. Funding and conflicts: Not stated in the abstract. Read: abstract
Zuo 2026 Biological-chemical method for synthesizing p-menthane-3,8-diol Synthetic and Systems Biotechnology · PMID 42182967 · DOI	Laboratory process paper lab	Engineered yeast and chemical catalysis	Citronellal made by yeast, then chemically converted to PMD n/a n/a Shake-flask cultivation · vs n/a	The abstract says the industrial production of PMD currently depends on chemically synthesized citronellal as a precursor. The authors made citronellal in yeast (0.13 g/L) and converted it to PMD (0.64 g/L). Lab yields only. Methods, limits and funding Outcomes: Citronellal and PMD yields Limitations: A manufacturing method, not a health study. Included only for how PMD is made. Funding and conflicts: Not stated in the abstract. Read: abstract
n/a 2022 CDC Travelers' Health: Avoid Bug Bites (wwwnc.cdc.gov/travel/page/avoid-bug-bites), page last reviewed 2022-05-11 n/a · Source	Regulator guidance page n/a	n/a	n/a n/a n/a n/a · vs n/a	Lists oil of lemon eucalyptus (OLE) and para-menthane-diol (PMD) among active ingredients of EPA-registered repellents that, when used as directed, are proven safe and effective, even for pregnant and breastfeeding women. Says: do not use products containing OLE or PMD on children under 3 years old; do not apply repellent to a child's hands, eyes, mouth, cuts or irritated skin; adults spray onto their own hands then apply to a child's face; if also using sunscreen, apply repellent after sunscreen. Methods, limits and funding Outcomes: What the CDC recommends for repellents and for children Limitations: The statements apply to EPA-registered repellent products, not to bottled essential oil. The CDC pages at cdc.gov/mosquitoes returned an access-denied error to our request, so only this Travelers' Health page was read. Read: full-text
n/a 2024 Poison Control (National Capital Poison Center): Essential oils: Poisonous when misused n/a · Source	Poison centre information page n/a	n/a	n/a n/a n/a n/a · vs n/a	Says misuse of essential oils can cause serious poisoning; many can cause rashes on skin and some are poisonous if absorbed through skin or swallowed; aspirating an essential oil can cause pneumonia; children have thin skin and immature livers and may be more susceptible; pure oils are potent, so diluting in a carrier oil is the best way to avoid a bad reaction; do not use on damaged skin; allergy is a real possibility and rash is the most common reaction; wash off with soap and water. It says it can be hard to know the species, concentration or contaminants in an essential oil bottle. States that swallowed eucalyptus oil can cause seizures. Poison help: 1-800-222-1222. Methods, limits and funding Outcomes: Essential oil poisoning, skin use, allergy Limitations: The eucalyptus statement is about eucalyptus oil in general and does not name lemon eucalyptus. Read: full-text
n/a 2025 EPA: Using Insect Repellents Safely and Effectively (page updated 2025-11-10) n/a · Source	Regulator guidance page n/a	n/a	n/a n/a n/a n/a · vs n/a	Says: apply only to exposed skin and clothing; do not apply near eyes and mouth; do not spray directly into the face; never use over cuts, wounds or irritated skin; do not spray in enclosed areas; do not use on pets unless the label says so; store out of children's reach. For children: do not let children handle the product or put it on their hands. According to product labels, some oil of lemon eucalyptus products should not be used on children under three, while there are no restrictions on under-3 use for certain products with OLE as the sole active ingredient at 30% or less. A registration number on the label means the company gave EPA technical information on effectiveness, and the CDC recommends EPA-registered products. Suggests asking a health care provider or the National Pesticide Information Center (1-800-858-7378) about concerns. Methods, limits and funding Outcomes: Safe-use directions, children, registration number Limitations: Regulator view of registered products. The EPA and CDC wording on children under 3 differs; follow the label. Read: full-text
n/a 2026 EPA: Skin-Applied Repellent Ingredients (page updated 2026-01-23) n/a · Source	Regulator guidance page n/a	n/a	n/a n/a n/a n/a · vs n/a	Lists p-menthane-3,8-diol (PMD; 6 products) and Oil of Lemon Eucalyptus (6 products), the latter described as containing PMD but being a separately regulated pesticide chemical, among active ingredients in EPA-registered skin-applied repellents. Methods, limits and funding Outcomes: Which repellent ingredients are EPA-registered Limitations: Names registered ingredients only. Says nothing about bottled essential oil. Read: full-text
n/a 2026 Pet Poison Helpline: Eucalyptus n/a · Source	Poison helpline information page n/a	n/a	n/a n/a n/a n/a · vs n/a	Says eucalyptus contains the essential oil eucalyptol; small ingestions of a few leaves or low concentration oil cause minor nausea; exposure (oral or dermal) to highly concentrated eucalyptus essential oil can cause severe signs including neurologic abnormalities and, rarely, kidney impairment. The page title says eucalyptus is toxic to cats. Methods, limits and funding Outcomes: Eucalyptus and pets Limitations: Genus-level page (Eucalyptus spp.). It does not name lemon eucalyptus or Corymbia. Read: full-text
n/a 2026 ASPCA Animal Poison Control: Eucalyptus n/a · Source	Poison centre information page n/a	n/a	n/a n/a n/a n/a · vs n/a	Lists Eucalyptus species as toxic to dogs, cats and horses; toxic principle essential oils (eucalyptol); signs include salivation, vomiting, diarrhea, depression and weakness. Methods, limits and funding Outcomes: Eucalyptus and pets Limitations: Genus-level entry (Eucalyptus). It does not name lemon eucalyptus or Corymbia. Read: full-text
n/a 2026 GBIF species match API: Corymbia citriodora (checked 2026-10-25) n/a · Source	Taxonomy database n/a	n/a	n/a n/a n/a n/a · vs n/a	Corymbia citriodora (Hook.) K.D.Hill & L.A.S.Johnson, key 5418431, status ACCEPTED, family Myrtaceae, exact match. Methods, limits and funding Outcomes: Accepted name Limitations: Name checking only. Read: full-text
n/a 2026 GBIF species match API: Eucalyptus citriodora (checked 2026-10-25) n/a · Source	Taxonomy database n/a	n/a	n/a n/a n/a n/a · vs n/a	Eucalyptus citriodora Hook., key 3180581, status SYNONYM, family Myrtaceae, accepted usage key 5418431 (Corymbia citriodora). Methods, limits and funding Outcomes: Older name Limitations: Name checking only. Read: full-text
n/a 2026 PubChem PUG REST name lookups (checked 2026-10-25) n/a · Source	Chemical database n/a	n/a	n/a n/a n/a n/a · vs n/a	Citronellal CID 7794 (C10H18O); citronellol CID 8842 (C10H20O); isopulegol CID 170833 (listed as (-)-isopulegol, C10H18O); 1,8-cineole (eucalyptol) CID 2758 (C10H18O); p-menthane-3,8-diol CID 556998 (C10H20O2); DEET CID 4284 (C12H17NO). Methods, limits and funding Outcomes: Compound identity Limitations: Identity only. PubChem lists one stereo form for isopulegol. Read: full-text

What we do not know yet

What the evidence supports: refined PMD products are moderate, lemon eucalyptus oil formulations low, and every other use low or insufficient.
No placebo-controlled trial of plain diluted lemon eucalyptus essential oil on skin was found.
No trial shows prevention of malaria, dengue or any disease with this oil or PMD.
No lemon eucalyptus-specific poisoning, pet, pregnancy or seizure report was found.
The PMD content of the raw oil differs between papers.
Many abstracts do not state funding or the number of volunteers.

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".

Other 4

●

Complete protection time (CPT)

Increase in trials

How long a repellent on the skin gives no mosquito bites or landings in a test.

Moderate certainty

Results and what it means

Why it was measured

The standard way to compare how long repellents last.

Statistical vs. clinical meaning

A practical measure, but times vary a lot with the test method, the mosquito and the amount applied.

Safety implication

A short protection time can leave a person unprotected without noticing.

Study	Result	People	Product
²	15% PMD and 15% DEET: median at least 6 hours in the field for both; in the cage test PMD 0.5 to 1 hour, DEET 0.5 to 2 hours.
⁶	32% lemon eucalyptus oil formulation: over 95% protection for 3 hours; 40% DEET: 100% for 7 hours.
⁵	2002 lab test: 23.8% DEET 301.5 minutes; most botanicals under 20 minutes.

^{2 6 5 9}

●

Bites or landings on treated skin

Decrease in trials

How many mosquitoes land on or bite treated skin compared with untreated skin or placebo.

Moderate certainty

Results and what it means

Why it was measured

Main outcome of the field trial in Senegal.

Statistical vs. clinical meaning

A direct measure, but it counts bites, not disease.

Safety implication

No serious adverse drug reaction was noticed in that trial.

Study	Result	People	Product
²¹	PMD 20% and 50%, icaridin 20% and DEET 50% each reduced bites versus placebo, with similar protection lasting 8 hours.

^{21 10}

●

Attached ticks found on the body

Decrease in trials

The number of ticks found attached to a person's skin, from a daily diary.

Low certainty

Results and what it means

Why it was measured

Main outcome of the Swedish tick trial.

Statistical vs. clinical meaning

Counts are self-reported and open-label.

Safety implication

Does not replace checking the body for ticks.

Study	Result	People	Product
⁸	42 attached ticks in spray weeks versus 112 in no-spray weeks; median 1.5 to 0.5 per person (P < 0.05).

⁸

●

Malaria infection and clinical cases

Decrease in trials

The rate of new Plasmodium falciparum infections and illness.

Not enough evidence

Results and what it means

Why it was measured

The disease outcome repellents are meant to prevent.

Statistical vs. clinical meaning

Shows the question has not been answered for this ingredient.

Safety implication

Use medical advice for malaria prevention.

Study	Result	People	Product
⁷	Repellents in general: pooled IRR 0.74 (0.56 to 0.98), low certainty. Not specific to lemon eucalyptus or PMD.

⁷

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 5

Bottled lemon eucalyptus oil and an EPA-registered 'oil of lemon eucalyptus' or PMD repellent are not the same product.. The EPA lists oil of lemon eucalyptus (OLE) and PMD as active ingredients in registered skin repellents, and says OLE contains PMD but is regulated as its own pesticide chemical. The CDC recommends EPA-registered repellents. Those statements are about tested, labelled products with a registration number on the label. They are not statements about a bottle of essential oil sold for aromatherapy or home-made sprays. Do not carry the regulator's view of a registered repellent over to the bottle. Authoritative guidance ^{27 26 24}
Not for children under 3 (OLE and PMD products), says the CDC.. The CDC says not to use products containing OLE or PMD on children under 3 years old, and not to put any repellent on a child's hands, eyes, mouth, cuts or irritated skin. The EPA says some OLE labels carry this under-3 warning, while there are no under-3 restrictions on certain products whose only active ingredient is OLE at 30% or less. The two wordings differ, so follow the label and ask a paediatrician or pharmacist. We found no source that makes bottled lemon eucalyptus essential oil safe for babies. Authoritative guidance ^{24 26}
Swallowing eucalyptus oil has caused drowsiness and seizures in young children.. None of the poisoning papers we read names lemon eucalyptus, and the oil in lemon eucalyptus is mostly citronellal rather than the compound that dominates ordinary eucalyptus oil. We found no lemon eucalyptus case. But Poison Control says swallowed eucalyptus oil can cause seizures. In 109 children admitted to a Melbourne hospital after swallowing eucalyptus oil, 59% had effects, 28% had lowered consciousness, 37% vomited and all recovered. In 17 children in India with seizures after taking eucalyptus oil drops by mouth, the seizures started a median of 20 minutes after exposure. Keep every essential oil locked away, and if anyone may have swallowed one, call Poison Help at 1-800-222-1222 (US) or your emergency number. Case series ^{25 20 18 16}
Skin: rash and allergy are the most likely harms; do not use the oil undiluted or on broken skin.. Poison Control says the most common allergic reaction to essential oils is a skin rash, that pure oils are potent and should be diluted in a carrier oil, and that they should not go on damaged skin. A Cochrane review of topical repellents (not specific to lemon eucalyptus) found mild skin reactions in 0.6% of 47,515 users. Citronellol, a compound in the oil, caused allergic patch-test reactions in 0.15% to 0.31% of 658 dermatitis patients when purified, and in 0.61% to 4.5% when oxidised, which means an old, air-exposed bottle may be more allergenic. These are clinic patients, not the general public. We do not give a dilution percentage. Authoritative guidance ^{25 7 12}
Keep it out of eyes and mouth, and keep pets away.. The EPA says not to apply repellents near the eyes and mouth, not to spray directly into the face, and not to use a product on pets unless the label says it is for animals. We found no lemon eucalyptus eye-injury report. Pet Poison Helpline says concentrated eucalyptus essential oil by mouth or on skin can cause severe signs in pets, and the ASPCA lists eucalyptus as toxic to dogs, cats and horses. Both pages are about eucalyptus in general and do not name lemon eucalyptus. Authoritative guidance ^{26 28 29}

Side effects 6

Effect	How often	Severity and recovery	Evidence
Allergic or irritant skin rash where the oil or repellent touched Poison Control says rash is the most common allergic reaction to essential oils.	Cochrane review of topical repellents in general: 0.6% (283 of 47,515), all mild skin reactions. Not specific to lemon eucalyptus.	mild to moderate Usually settles when contact stops and the skin is washed.	Meta-analysis ^{7 25}
Allergic skin reaction to citronellol, a compound in the oil (especially when oxidised) The test was on citronellol alone, not lemon eucalyptus oil.	0.15% to 0.31% of 658 dermatitis patients (purified); 0.61% to 4.5% (oxidised). Clinic patients, not the general public.	mild to moderate Allergy tends to persist.	Observational ¹²
Seizures after swallowing, breathing or skin exposure to eucalyptus oil (species not named in the papers) Not shown for lemon eucalyptus oil. No lemon eucalyptus case was found.	Pooled 110 case reports; 17 children in one Indian series. The rate is not known.	severe Most recovered; one child recovered quickly after the skin was washed.	Case series ^{16 18 22}
Drowsiness, vomiting, unsteadiness and lung problems after a child swallowed eucalyptus oil Species not named in the abstract.	In 109 children: lowered consciousness 28%, vomiting 37%, ataxia 15%, lung disease 11%.	moderate to severe All 109 recovered; mean hospital stay 22 hours.	Case series ²⁰
Eye or mouth irritation from sprays and wipes The EPA's advice is to keep repellents away from eyes and mouth. We found no lemon eucalyptus-specific eye report.	No rate found.	not rated Not described.	Authoritative guidance ²⁶
Pneumonia if oil is breathed into the lungs while swallowing Poison Control states this for essential oils in general.	No rate found.	severe Not described.	Authoritative guidance ²⁵

Liver

We found no report of liver injury from lemon eucalyptus oil or PMD. We did not find or read a LiverTox entry for them. Absence of reports is not proof of safety. ²⁵

How often. No cases found.

Monitoring. Yellow skin or eyes, dark urine, severe tiredness or pain in the upper right belly after swallowing any oil needs a doctor.

This is a safety connection. It is not evidence that Lemon Eucalyptus Oil (and PMD) supports liver health.

Medicines and supplements 2

With	Why it matters	Importance	Evidence	What to do
Any prescribed medicines, especially for seizures medicines and supplements	No interaction of lemon eucalyptus oil or PMD with medicines was described in any source we read.	Unknown.	None found Not enough evidence ¹⁶	Tell a pharmacist about any essential oil or repellent you use, especially if you or a child have epilepsy or take medicines for seizures, because eucalyptus oil seizures have been reported.
Sunscreen other skin products	The CDC advises applying insect repellent after sunscreen.	This is a regulator application tip; no interaction data were found.	Authoritative guidance Not enough evidence ²⁴	Follow the product label and the CDC tip.

Who should check first 6

Situation	Advice	Evidence
Child under 3 years old (OLE or PMD repellent products)	The CDC says do not use. Follow the label and ask a paediatrician.	Authoritative guidance ^{24 26}
Swallowing, or putting in a child's mouth or on hands, eyes or mouth	Do not swallow bottled oil. Call poison help if swallowed.	Case series ^{25 20 18}
Cuts, wounds, irritated or damaged skin	Do not use. The EPA and Poison Control both say this.	Authoritative guidance ^{26 25}
Known allergy to essential oils, fragrances or citronellol	Avoid. Ask a doctor about patch testing.	Observational ¹²
Epilepsy or seizure history	No lemon eucalyptus source exists, but eucalyptus oil seizures are reported. Ask a doctor before using any eucalyptus oil.	Case series ^{16 18}
Homes with cats, dogs, birds or horses	Keep oils, repellents and diffusers away from pets. Do not put a repellent on a pet unless the label says it is for animals.	Authoritative guidance ^{26 28 29}

Overdose, product quality and regulators

Summary. Poisoning data are for eucalyptus oil in general. No lemon eucalyptus poisoning case was found. Swallowing is the main danger for young children; skin allergy is the best-documented harm in adults.

Amounts. No safe amount is established, and this page gives none.

Onset and course. In 17 children with seizures after eucalyptus oil by mouth, onset was a median of 20 minutes. For pets, onset times for lemon eucalyptus were not found.

Repeated use. Allergy can develop with repeated skin contact according to Poison Control and patch-test reports.

Animal data. Pet Poison Helpline and the ASPCA warn about eucalyptus oil in pets. In cells and zebrafish embryos, PMD was less toxic than DEET; that does not show human safety.

Toxic parts. The concentrated essential oil is the risk form. Registered repellents contain the oil or PMD at product strengths set on the label.

Not read. LiverTox, LactMed, EMA assessment, NPIC fact sheets and any lemon-eucalyptus-specific poison centre statement were not found or not read.

The oil in a bottle can differ from the label, and the registered repellents are made differently from the raw oil.

Unknown species, strength and contaminants. Poison Control says it can be hard to know the species, concentration or contaminants in an essential oil bottle. ²⁵

Oil makeup varies. Citronellal was 56% of one Egyptian leaf oil and 38% to 48% of another oil made by two distillation methods. Other main compounds named were citronellol, isopulegol and eucalyptol. ^{19 13}

Registered product versus bottle. A registered repellent has an EPA registration number; the EPA says it means the company gave technical information on effectiveness. A bottled essential oil has no such number. ²⁶

Old or air-exposed oil. Oxidised citronellol caused more patch-test allergy than purified citronellol, and the authors say citronellol is susceptible to autoxidation. ¹²

Look-alike eucalyptus oils. Ordinary eucalyptus oil and lemon eucalyptus oil are different oils from different trees. The poisoning reports we read do not say which species was involved. ^{28 20}

Body	Action	Date
US CDC, Travelers' Health: Avoid Bug Bites (United States)	Lists OLE and PMD among EPA-registered repellent ingredients proven safe and effective when used as directed, even for pregnant and breastfeeding women; says do not use OLE or PMD products on children under 3 years old. source	2022-05-11
US EPA, Skin-Applied Repellent Ingredients (United States)	Lists PMD and Oil of Lemon Eucalyptus as separately regulated active ingredients in registered skin repellents (6 products each); OLE contains PMD. source	2026-01-23
US EPA, Using Insect Repellents Safely and Effectively (United States)	Safe-use rules, children's statements, OLE under-3 label wording, registration number meaning. source	2025-11-10
Poison Control (National Capital Poison Center) (United States)	Essential oils can cause serious poisoning when misused; dilute pure oils; avoid damaged skin; swallowed eucalyptus oil can cause seizures. source	n/a
Pet Poison Helpline (United States)	Concentrated eucalyptus essential oil can cause severe signs in pets. source	n/a
ASPCA Animal Poison Control (United States)	Lists Eucalyptus as toxic to dogs, cats and horses. source	n/a

When to get medical help

If a child or pet may have swallowed any essential oil or repellent, call poison control (US: 1-800-222-1222; pets: ASPCA 888-426-4435 or Pet Poison Helpline 855-764-7661) or your emergency number.
A seizure, collapse, severe drowsiness, or trouble breathing after any eucalyptus oil or repellent exposure is an emergency.
Coughing, choking, or fast breathing right after a child swallows oil may mean oil has entered the lungs: seek emergency help.
Swelling of the lips, tongue or face, or a spreading rash after contact: stop use, wash off and get help.
Repellent in the eyes: rinse with water as the label says and get advice. A blistering or weeping skin rash needs a doctor.

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 lemon eucalyptus oil the same as PMD or an 'oil of lemon eucalyptus' repellent?

No. The oil is distilled from the leaves. PMD is the repellent compound that industry makes from a compound in the oil. The EPA says oil of lemon eucalyptus contains PMD but is regulated as a separate pesticide chemical. A registered repellent has a registration number on its label; a bottle of essential oil does not.

^{27 23 26}

Does it repel mosquitoes as well as DEET?

PMD sprays protected about as well as DEET in a 100-person placebo-controlled trial in Senegal (a non-significant trend favoured DEET 50% over PMD 20%). In Queensland a lemon eucalyptus oil product gave over 95% protection for 3 hours against 7 hours for 40% DEET. Reviews say plant-based repellents usually last two to four hours against five to nine for DEET. Times vary by product.

^{21 6 4}

Is it safe for babies and young children?

The CDC says not to use products containing OLE or PMD on children under 3 years old. The EPA says some OLE labels carry the warning and certain products with OLE alone at 30% or less do not. Follow the label and ask a paediatrician. We found no source that makes bottled essential oil safe for babies.

^{24 26}

Can I swallow it or use it undiluted on skin?

No. We do not advise swallowing essential oils. Poison Control says swallowed eucalyptus oil can cause seizures, pure oils are potent and should be diluted in a carrier oil, and they should not go on damaged skin. If anyone may have swallowed some, call Poison Help at 1-800-222-1222 (US) or your emergency number.

^{25 20 18}

Is it safe for cats and dogs?

Not shown to be safe. Pet Poison Helpline says concentrated eucalyptus essential oil by mouth or on skin can cause severe signs in pets, and the ASPCA lists eucalyptus as toxic to dogs, cats and horses. Those pages are about eucalyptus in general. Keep oils, repellents and diffusers away from pets and ask a vet.

^{28 29}

Is it safe in pregnancy or while breastfeeding?

The CDC says EPA-registered repellents, including those with OLE or PMD, are proven safe and effective when used as directed, even for pregnant and breastfeeding women. That covers registered products. We found no source on the bottled oil in pregnancy or breastfeeding. Ask a doctor or midwife.

²⁴

Can it cause a rash or allergy?

Yes, it can. Poison Control says rash is the most common allergic reaction to essential oils. A Cochrane review of topical repellents in general found mild skin reactions in 0.6% of users. A compound in the oil, citronellol, caused patch-test allergy in a small share of dermatitis patients, more when oxidised. Wash off and stop if a rash appears.

^{25 7 12}

Does it repel ticks?

An open trial of a refined lemon eucalyptus extract spray in 111 Swedish adults found fewer attached ticks reported (42 versus 112), but there was no placebo and ticks were counted from diaries. Evidence is low. A repellent does not replace checking for ticks.

⁸

Does it prevent malaria or dengue?

Not shown. A Cochrane review found topical repellents in general may slightly reduce malaria, with low-certainty evidence, and its abstract does not name lemon eucalyptus or PMD. Ask a travel clinic about proper protection.

⁷

Is lemon eucalyptus the same as ordinary eucalyptus oil?

No. They come from different trees and the oils differ. The ASPCA names eucalyptol as the toxic principle of eucalyptus, and eucalyptol was one of several main compounds in a lemon eucalyptus oil analysis, but citronellal was the largest. The poisoning reports do not say which species was used, so treat both oils with the same caution.

^{29 19 20}

Is a home-made lemon eucalyptus spray as good as a registered repellent?

Not shown. We found no placebo-controlled trial of plain diluted lemon eucalyptus essential oil, and the EPA registration number marks tested products. We give no recipe.

^{26 6}

Does the scent help with mood, sleep, breathing or pain?

We found no human trial of lemon eucalyptus oil as a scent for these. A computer study predicted that compounds in the oil could bind inflammation-related enzymes, but nobody has tested it in animals or people.

¹³

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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 read the abstracts of 23 PubMed papers and the CDC Travelers' Health, EPA, Poison Control, Pet Poison Helpline and ASPCA pages, and checked the tree name in GBIF and the compounds in PubChem. We could not read the CDC mosquito pages or find LiverTox, LactMed or EMA statements for this oil.
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 or assessments linked to industry are labelled.

Sources 32

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

Carroll SP, Venturino J, Davies JH. A Milestone In Botanical Mosquito Repellents: Novel PMD-Based Formulation Protects More Than Twice As Long As High-Concentration Deet and Other Leading Products. Journal of the American Mosquito Control Association. 2019. PMID 31647713. DOI 10.2987/19-6824.1. (abstract)
Colucci B, Mueller P. Evaluation of standard field and laboratory methods to compare protection times of the topical repellents PMD and DEET. Scientific Reports. 2018. PMID 30135603. DOI 10.1038/s41598-018-30998-2. (abstract)
Elmhalli FH, Palsson K, Orberg J, Jaenson TG. Acaricidal effects of Corymbia citriodora oil containing para-menthane-3,8-diol against nymphs of Ixodes ricinus. Experimental & Applied Acarology. 2009. PMID 19169833. DOI 10.1007/s10493-009-9236-4. (abstract)
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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.