Essential Oils & Aromatherapy · Essential oil
Sweet Marjoram Oil
Origanum majorana L. · also called Sweet marjoram oil, marjoram oil, marjoram essential oil
Sweet marjoram oil is a warm, herb-like essential oil made from the leaves of a kitchen herb in the mint family. People use it in scent and in diluted massage blends, and try it for stress and period cramps. The research is small: one nurse trial of the oil alone gave no clear anxiety benefit, and the other trials used blends. The main caution: the European food safety agency says to treat the oil as a skin, eye and breathing irritant, and it must never be swallowed.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Sweet Marjoram Oil
Sweet marjoram oil is a warm, herb-like scent made from the leaves of a kitchen herb. Small studies looked at stress in nurses and at period pain, but only one tested the oil alone, and it found no clear anxiety benefit compared with a plain oil. Safety comes first: EFSA says treat the oil as an irritant and a sensitiser, it must not be swallowed, and its safety in pregnancy is not established.
What sweet marjoram oil is
The oil comes from Origanum majorana, a plant in the mint family (Lamiaceae, per GBIF). EFSA assessed an oil from the leaves.
The oil is a mixture. Papers name terpinen-4-ol, sabinene, trans-sabinene hydrate and linalyl acetate among its compounds. The mix changes a lot: researchers found at least 5 chemotypes (kinds) of marjoram oil.
The leaves are recognised as a food flavouring (EFSA). That is not the same as swallowing the concentrated oil.
What people use it for, and how strong the evidence is
For stress, the one trial of marjoram alone (57 ICU nurses, 2 hours of 3% oil against almond oil) found no significant difference between groups in anxiety. A 2026 review of aromatherapy in ICU nurses calls the anxiety evidence mixed. A four-oil mixture that included marjoram was followed by better well-being in 49 hospital staff, but the study was open-label.
For period pain, two small trials used massage with blends that included marjoram. Pain fell, but a fragrance-only cream also helped in one, and in the other the comparison was a painkiller tablet. Nothing can be credited to marjoram alone.
A tiny study of massage with a marjoram blend found changes in some white blood cells; this is a lab marker. Test-tube work shows germ-slowing action in a dish, not in the body. We found no human study of marjoram oil for constipation or sleep.
The research in one view
Only one human trial tested marjoram oil alone. It was small and short, and a scent is hard to hide from a comparison group. Every other human study used a blend, so none can be credited to marjoram.
No large independent trial and no meta-analysis of marjoram oil alone was found.
Blends, kinds of oil and bottles are different things
Several trials tested blends with lavender, clary sage, ginger, cinnamon, geranium, cypress or others. Their results do not describe marjoram oil alone.
Marjoram oil varies by plant and growing conditions. A study of oils from Nepal and published analyses found at least 5 chemotypes, and the leading compound differed between oils (trans-sabinene hydrate in some, terpinen-4-ol in others). Poison Control says it can be hard to know the species, strength and contaminants in a bottle. Oregano is a different plant with a different oil.
What regulators say
EFSA's 2025 animal-feed opinion found marjoram oil very unlikely to cause adverse effects in animals at the proposed feed level, saw no concern for consumers or the environment, and said the oil should be treated as an irritant and a sensitiser, with estragole exposure for handlers to be minimised. This is about feed, not diffusers or skin products.
We did not find or read a statement from IFRA, the EU cosmetics regulator, FDA, NCCIH or EMA about this oil.
At a glance
Traditional uses history, not proof
- The leaves are recognised as a food flavouring (EFSA).
- The authors of a 2023 nurse trial say marjoram oil has been reported to have calming effects; their abstract gives no source.
- We did not find a traditional-medicine history for the oil in the sources read, so none is claimed.
Studied for research
- Stress and anxiety in ICU nurses, inhaled, very-low
- Staff well-being, a four-oil mixture, very-low
- Period pain, blends only, very-low
- Anxiety and low mood after a blend massage, insufficient
- Blood immune-cell counts after a blend massage, insufficient
- Germ-killing in the laboratory, insufficient
Main compounds
- Terpinen-4-ol, a main compound in several oils
- Sabinene, found in several oils
- trans-Sabinene hydrate, a leading compound in two oils
- Linalyl acetate, found in one oil
Common forms
- Essential oil (from the leaves, per EFSA)
- Scent from a diffuser or stick
- Diluted massage blends with other oils
- Cosmetic and fragrance products
Research links: Poison Control: Essential oils · EFSA opinion on marjoram oil (abstract) · Pet Poison Helpline: Essential oils · Marjoram oil and ICU nurses, randomised trial (abstract) · Aromatherapy for ICU nurses, systematic review (abstract) · Essential oils and contact allergy, review (abstract) · GBIF: Origanum majorana · Research Library · Genes & Biomarkers Library
What it is and its history
- Accepted scientific name
- Origanum majorana
- Naming authority
- L.
- Common names
- Sweet marjoram (English); Marjoram (English)
- Family or group
- Lamiaceae (the mint family), per GBIF. The 1996 case report calls the family Labiatae.
- Classification
- Plantae > Tracheophyta > Magnoliopsida > Lamiales > Lamiaceae > Origanum > Origanum majorana
- Native range
- Not checked in a source read for this page.
- Habitat
- Not checked in a source read.
- What it looks like
- Part used: EFSA assessed an essential oil from the leaves. One 2022 paper calls its sample marjoram herb oil. This page does not describe how to recognise the plant.
- Look-alikes and adulterants
- Name: Oregano (Origanum vulgare) and other Origanum species and hybrids; Note: Related plants with their own oils and different main compounds; results do not carry between them. A source on how often oils are confused or mislabelled was not read.
- Sustainability and conservation
- Not checked (no IUCN or CITES source read).
Photographs
Traditional use and history history, not clinical proof
| Tradition or era | Documented use | Source |
|---|---|---|
| Food flavouring | EFSA says the leaves of O. majorana and their preparations are recognised to flavour food. | EFSA FEEDAP Panel 2025 (abstract) |
| Modern aromatherapy research | The authors of the 2023 nurse trial say inhaled marjoram oil has been reported to have calming effects; the abstract gives no source. Traditional-medicine history of the plant was not found in a source read, so none is claimed. | Lee et al. 2023 (abstract) |
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 |
|---|---|---|---|---|
| Terpinen-4-ol PubChem 11230 | monoterpene alcohol | Essential oil About 18% to 25% in oils analysed in two papers; named a main compound in a third. Varies. | Slowed bacterial growth and biofilm in test tubes. No effect in people was read. 19 7 6 13 14 | Laboratory |
| Sabinene PubChem 18818 | bicyclic monoterpene | Essential oil 4.53% in one oil; named a main compound in another paper. | In a laboratory test it blocked a bacterial efflux pump in a sensitive E. coli strain and slowed biofilm. No effect in people was read. 19 7 14 | Laboratory |
| trans-Sabinene hydrate | monoterpene alcohol | Essential oil 25.18% and 36.11% in two oils. | Listed among the largest components in two oils; the sabinene hydrate form slowed biofilm in the test tube. The PubChem CID was not checked. 7 6 | Laboratory |
| Linalyl acetate | monoterpene ester | Essential oil 9.18% in one oil. | A component of that oil; its own activity was not described in the abstract. 6 | Laboratory |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| Bacterial growth, efflux pumps and biofilm (test tube) | Not specified | Marjoram oil and some single compounds slowed growth of sensitive and drug-resistant S. aureus and E. coli; sabinene was an efflux-pump inhibitor in one E. coli strain; effects on biofilm differed by strain and between oil and single compounds. 7 | Laboratory research |
| Fungi and antioxidant tests (test tube) | Not specified | A Nepalese oil slowed Aspergillus niger and Candida albicans and showed moderate antioxidant activity. 13 | Laboratory research |
| Helicobacter pylori (test tube and computer) | Urease and CagA (computer docking) | Marjoram oil slowed H. pylori in the test tube and combined with mandarin oil gave synergy; docking is a prediction, not proof. 6 | Laboratory research |
| How a scent might calm people | Not specified | No mechanism in people was tested. In the nurse trial anxiety did not differ between the marjoram and almond oil groups, so there is no proven effect to explain. 10 | Not assessed |
Absorption, metabolism and elimination
- Absorption
- Not established in the sources read.
- Distribution
- Not established.
- Metabolism
- Not established.
- Elimination
- Not established.
- Bioavailability
- Not established.
Isolated compounds versus whole extracts
The oil is a mixture, and its makeup changes with variety, growing conditions and light. The 2022 papers found different leading compounds (trans-sabinene hydrate or terpinen-4-ol) and at least 5 chemotypes. In one test-tube study the whole oil and single compounds acted differently on biofilm. Results for one compound or one blend do not describe another oil.
Nutritional composition
Marjoram oil is not a nutrient and is not an ingredient to swallow for health. EFSA says the leaves are recognised to flavour food, which is different from swallowing the concentrated oil.
1 mixed findings3 very low certainty3 not enough evidence
What was looked at
The 7 benefits and uses checked for Sweet Marjoram Oil, each with how strong the evidence is. Tap one to open it.
- Stress and anxiety in ICU nurses (smelling 3% marjoram oil at work)Very low certainty
- Aromatherapy for ICU nurses: the wider evidence (many oils)Mixed findings
- Well-being and stress in hospital staff (a four-oil mixture with marjoram)Very low certainty
- Anxiety and low mood after aromatherapy massage (a lavender, cypress and marjoram blend)Not enough evidence
- Period pain (abdominal massage with marjoram-containing blends)Very low certainty
- Blood immune-cell counts after aromatherapy massage (a blend with sweet marjoram)Not enough evidence
- Germ-killing and antioxidant action in the laboratoryNot enough evidence
Lab markers tracked in the studies
Anxiety and stress scores (STAI, visual scales, WHO-5)Heart rate and mean arterial pressureMenstrual pain scores (numeric, verbal and visual scales)Lymphocyte counts (CD8+, CD16+, CD4+/CD8+ ratio)
What is Sweet Marjoram Oil good for?
The uses people ask about and how strong the evidence is for each. Read the certainty label first: nothing here is better than very low, and most results come from blends.
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.
Stress and anxiety in ICU nurses (smelling 3% marjoram oil at work)
Very low certaintyIn one trial of 57 intensive care nurses, 2 hours of breathing in 3% marjoram oil gave no clear difference in anxiety compared with almond oil. Scores did fall within the marjoram group compared with before, but that is a weaker kind of result.
1 studiesNot covered. This page gives no amounts and no way to use the oil.
Studies, doses and limits
What the trials found
One randomised trial: 57 nurses in a single COVID-19 intensive care unit, 29 marjoram and 28 almond-oil (control), one 2-hour session.
Results
After the 2 hours there was no significant difference between groups in state anxiety or in the anxiety visual scale. Within the marjoram group, state anxiety, anxiety and stress scores were lower than before (p = 0.001, 0.037 and 0.026). Blood pressure (mean arterial pressure) did not change. Heart rate rose slightly in the marjoram group (p = 0.031) but stayed in the normal range.
Effect sizes as reported
No effect sizes in the abstract; the between-group anxiety result was not significant.
Why this rating
One small, single-hospital trial and one session. The fair test (between groups) was not significant for anxiety. A smell is hard to hide, so nurses probably knew their group.
Form and dose studied
Not covered. This page gives no amounts and no way to use the oil.
Who was studied
Working nurses in one hospital unit, not people with an anxiety disorder.
Limits
The authors conclude the oil 'may be' a simple, effective intervention, which is more positive than the between-group result. Short, one session, self-rated.
Why researchers looked
ICU nurses carry heavy stress, and a scent is cheap and easy to offer.
Traditional use
The trial authors say there is evidence that marjoram oil has calming effects; the abstract does not give the source.
Proposed mechanism Preliminary mechanism
Not established. Smell and expectation may play a part; no mechanism was tested in this trial.
A proposed mechanism does not show that the effect happens in people.
Heart rate rose slightly in the marjoram group (still in the normal range). Marjoram oil is a skin and breathing sensitiser for people who handle it (see Safety).
Aromatherapy for ICU nurses: the wider evidence (many oils)
Mixed findingsA 2026 review of five studies (254 nurses) says aromatherapy may lower stress, but evidence for less anxiety is mixed and inconsistent. It covered many oils and methods, not marjoram alone.
1 studiesNot covered. This page gives no amounts and no way to use the oil.
Studies, doses and limits
What the trials found
One systematic review: two randomised trials and three quasi-experimental studies, various oils, inhaled or on the skin.
Results
Aromatherapy may reduce stress among ICU nurses; evidence for lower anxiety is mixed and less consistent across studies. The authors say higher-quality studies are needed before firm conclusions.
Why this rating
Few studies, different oils and methods, and the reviewers themselves call the anxiety evidence limited and inconsistent. It does not isolate marjoram.
Form and dose studied
Not covered. This page gives no amounts and no way to use the oil.
Who was studied
ICU nurses.
Limits
Only the abstract was read. The abstract does not say which studies used marjoram.
Why researchers looked
To see whether scent-based approaches help stressed intensive care staff.
Proposed mechanism Preliminary mechanism
Not assessed.
A proposed mechanism does not show that the effect happens in people.
Aromatherapy review also asks for attention to scent sensitivity.
Well-being and stress in hospital staff (a four-oil mixture with marjoram)
Very low certaintyIn 49 hospital staff, a stick with sweet orange, lavender, marjoram and ylang ylang for 2 months was followed by better well-being scores than a 2-month period with nothing. The study was open-label, so nobody was blinded, and it cannot show what marjoram did.
1 studiesNot covered. This page gives no amounts and no way to use the oil.
Studies, doses and limits
What the trials found
One randomised, open-label crossover trial: 51 randomised, 49 analysed.
Results
The WHO-5 well-being score was higher in the aromatherapy period than the control period (65.9 vs 60.4, p = 0.0142). General anxiety and perceived stress scores were also significantly lower.
Effect sizes as reported
WHO-5 least-square means 65.9 vs 60.4.
Why this rating
A blend, so no credit to marjoram; open-label with self-rated outcomes; one hospital that also funded the work.
Form and dose studied
Not covered. This page gives no amounts and no way to use the oil.
Who was studied
Staff in emergency, intensive care, anaesthesia and operating theatre departments in France.
Limits
No inert comparison and no blinding; the authors say larger, more robust studies are needed.
Why researchers looked
Burnout is common among hospital staff.
Proposed mechanism Preliminary mechanism
Not assessed.
A proposed mechanism does not show that the effect happens in people.
A four-oil mixture; skin and breathing sensitising effects apply to each oil (see Safety).
Anxiety and low mood after aromatherapy massage (a lavender, cypress and marjoram blend)
Not enough evidenceIn 11 people, anxiety and depression scores fell after both an aromatherapy massage (with sweet marjoram, lavender and cypress) and a plain carrier-oil massage. There was no difference between the two.
1 studiesNot covered. This page gives no amounts and no way to use the oil.
Studies, doses and limits
What the trials found
One small preliminary comparison (11 people).
Results
STAI anxiety and SDS depression scores fell significantly after both massages (P < 0.01), with no difference between aromatherapy and carrier massage.
Why this rating
Eleven people, a blend, and no difference from plain massage.
Form and dose studied
Not covered. This page gives no amounts and no way to use the oil.
Who was studied
Eleven recipients of massage.
Limits
Preliminary, tiny, and a blend with massage.
Why researchers looked
Massage with scented oils is a common way to relax.
Proposed mechanism Preliminary mechanism
Not established. The fall in both groups points to the massage itself or to expectation.
A proposed mechanism does not show that the effect happens in people.
Skin use raises the allergy question (see Safety).
Period pain (abdominal massage with marjoram-containing blends)
Very low certaintyTwo small trials used belly massage with blends that included marjoram oil. Pain scores fell, but in one trial they also fell with a fragrance-only cream, and in the other the comparison was a painkiller tablet. Marjoram on its own was not tested.
2 studiesNot covered. This page gives no amounts and no way to use the oil.
Studies, doses and limits
What the trials found
Two small trials: 48 women with a lavender, clary sage and marjoram cream (3%) against a fragrance cream, and 55 high school girls with a five-oil blend (clary sage, marjoram, cinnamon, ginger, geranium) against acetaminophen.
Results
Trial 1: pain scales fell in both groups after one cycle (P < 0.001); pain lasted 1.8 days instead of 2.4 in the oil group. Trial 2: after one massage, pain fell more than in the acetaminophen group, though the authors say they could not tell whether the benefit came from the oils, the massage or both.
Effect sizes as reported
No between-group numbers in the abstracts.
Why this rating
Blends of three or five oils plus massage, small samples, a fragrance-only group that improved too, and a non-blinded comparison with a medicine. Marjoram's own part cannot be separated.
Form and dose studied
Not covered. This page gives no amounts and no way to use the oil.
Who was studied
Women with primary period pain; Korean high school girls.
Limits
Only abstracts read. Not a reason to skip medical advice for severe or new period pain.
Why researchers looked
Warm abdominal massage with scented oils is a popular home approach to period cramps.
Proposed mechanism Preliminary mechanism
Not established. The 2012 authors list analgesic-type components of their blend (linalyl acetate, linalool, eucalyptol, beta-caryophyllene); marjoram is not named as the source and this was not tested.
A proposed mechanism does not show that the effect happens in people.
Pregnancy: oils are not shown to be safe (see Safety). Skin use raises the allergy question.
Blood immune-cell counts after aromatherapy massage (a blend with sweet marjoram)
Not enough evidenceIn 11 people, aromatherapy massage with sweet marjoram, lavender and cypress was followed by a rise in some white blood cell types compared with plain massage. This is a lab marker, not a health outcome.
1 studiesNot covered. This page gives no amounts and no way to use the oil.
Studies, doses and limits
What the trials found
One preliminary study, 11 recipients.
Results
Peripheral blood lymphocytes rose, with CD8+ and CD16+ cells up and the CD4+/CD8+ ratio down, after aromatherapy massage and not after carrier-oil massage. The authors call for a larger, prospective study.
Why this rating
Eleven people, a blend, and a lab marker whose meaning for health was not shown.
Form and dose studied
Not covered. This page gives no amounts and no way to use the oil.
Who was studied
Eleven people receiving massage.
Limits
A change in cell counts is not evidence of better immunity or fewer infections.
Why researchers looked
Researchers wanted to see whether massage with oils changes immune cells.
Proposed mechanism Preliminary mechanism
Not established.
A proposed mechanism does not show that the effect happens in people.
None specific.
Germ-killing and antioxidant action in the laboratory
Not enough evidenceIn test tubes and computer models, marjoram oil slowed several bacteria and fungi and showed antioxidant activity. None of this shows an effect in people.
3 studiesNot covered. This page gives no amounts and no way to use the oil.
Studies, doses and limits
Results
Oil from Nepal slowed Aspergillus niger and Candida albicans (MIC 78.1 ug/mL in one sample). A marjoram oil slowed sensitive and drug-resistant S. aureus and E. coli; biofilm effects varied by strain. In another study, marjoram oil slowed Helicobacter pylori in the test tube and was synergistic with mandarin oil.
Effect sizes as reported
Test-tube MIC values only.
Why this rating
Test-tube and computer work only; concentrations in a dish are not what reaches the body.
Form and dose studied
Not covered. This page gives no amounts and no way to use the oil.
Limits
Does not show treatment of any infection. The marjoram oils tested had different compositions.
Why researchers looked
Many plant oils are screened as possible natural preservatives or germ-fighters.
Traditional use
The Nepal authors suggest a use as a natural preservative in food and medicine; that is their suggestion, not a tested use.
Proposed mechanism Preliminary mechanism
Terpinen-4-ol, sabinene and sabinene hydrate were among compounds that slowed bacterial growth or biofilm in the test tube; the whole oil and single compounds behaved differently.
A proposed mechanism does not show that the effect happens in people.
Test-tube activity does not make the oil safe or useful on the body.
Connections to the rest of health
How Sweet Marjoram Oil connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.
Explore every connection: goals, body systems, organs, symptoms, genes
A. Wellness goals
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Stress Reduction | Very low certainty | Stress and anxiety in ICU nurses (smelling 3% marjoram oil at work): In one trial of 57 intensive care nurses, 2 hours of breathing in 3% marjoram oil gave no clear difference in anxiety compared with almond oil. Scores did fall within the marjoram group compared with before, but that is a weaker kind of result. Well-being and stress in hospital staff (a four-oil mixture with marjoram): In 49 hospital staff, a stick with sweet orange, lavender, marjoram and ylang ylang for 2 months was followed by better well-being scores than a 2-month period with nothing. The study was open-label, so nobody was blinded, and it cannot show what marjoram did. | 10 1 | |
| Anxiety Support | Very low certainty | Stress and anxiety in ICU nurses (smelling 3% marjoram oil at work): In one trial of 57 intensive care nurses, 2 hours of breathing in 3% marjoram oil gave no clear difference in anxiety compared with almond oil. Scores did fall within the marjoram group compared with before, but that is a weaker kind of result. | 10 | |
| Stress Reduction | Mixed findings | Aromatherapy for ICU nurses: the wider evidence (many oils): A 2026 review of five studies (254 nurses) says aromatherapy may lower stress, but evidence for less anxiety is mixed and inconsistent. It covered many oils and methods, not marjoram alone. | 2 | |
| Anxiety Support | Mixed findings | Aromatherapy for ICU nurses: the wider evidence (many oils): A 2026 review of five studies (254 nurses) says aromatherapy may lower stress, but evidence for less anxiety is mixed and inconsistent. It covered many oils and methods, not marjoram alone. | 2 | |
| Mood Balance | Very low certainty | Well-being and stress in hospital staff (a four-oil mixture with marjoram): In 49 hospital staff, a stick with sweet orange, lavender, marjoram and ylang ylang for 2 months was followed by better well-being scores than a 2-month period with nothing. The study was open-label, so nobody was blinded, and it cannot show what marjoram did. | 1 | |
| Anxiety Support | Not enough evidence | Anxiety and low mood after aromatherapy massage (a lavender, cypress and marjoram blend): In 11 people, anxiety and depression scores fell after both an aromatherapy massage (with sweet marjoram, lavender and cypress) and a plain carrier-oil massage. There was no difference between the two. | 9 | |
| Mood Balance | Not enough evidence | Anxiety and low mood after aromatherapy massage (a lavender, cypress and marjoram blend): In 11 people, anxiety and depression scores fell after both an aromatherapy massage (with sweet marjoram, lavender and cypress) and a plain carrier-oil massage. There was no difference between the two. | 9 | |
| Womens Wellness | Very low certainty | Period pain (abdominal massage with marjoram-containing blends): Two small trials used belly massage with blends that included marjoram oil. Pain scores fell, but in one trial they also fell with a fragrance-only cream, and in the other the comparison was a painkiller tablet. Marjoram on its own was not tested. | 12 8 | |
| Pain Relief | Very low certainty | Period pain (abdominal massage with marjoram-containing blends): Two small trials used belly massage with blends that included marjoram oil. Pain scores fell, but in one trial they also fell with a fragrance-only cream, and in the other the comparison was a painkiller tablet. Marjoram on its own was not tested. | 12 8 | |
| Immune Support | Not enough evidence | Blood immune-cell counts after aromatherapy massage (a blend with sweet marjoram): In 11 people, aromatherapy massage with sweet marjoram, lavender and cypress was followed by a rise in some white blood cell types compared with plain massage. This is a lab marker, not a health outcome. | 9 | |
| Immune Support | Not enough evidence | Germ-killing and antioxidant action in the laboratory: In test tubes and computer models, marjoram oil slowed several bacteria and fungi and showed antioxidant activity. None of this shows an effect in people. | 13 7 6 |
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Nervous System | Biological association | Very low certainty | Studied for: Stress and anxiety in ICU nurses (smelling 3% marjoram oil at work) Studied for: Aromatherapy for ICU nurses: the wider evidence (many oils) | 10 2 1 9 |
| Reproductive System | Biological association | Very low certainty | Studied for: Period pain (abdominal massage with marjoram-containing blends) | 12 8 |
| Immune System | Biological association | Not enough evidence | Studied for: Blood immune-cell counts after aromatherapy massage (a blend with sweet marjoram) Studied for: Germ-killing and antioxidant action in the laboratory | 9 13 7 6 |
E. Health conditions
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Contact dermatitis | Adverse effect or risk | Documented risk | EFSA: dermal sensitiser for handlers. Reviews link most essential oil contact allergy to pure or high-concentration products. Preparation or compound: Marjoram oil on the skin |
4 16 |
| Pregnancy | Not enough evidence | Safety in pregnancy not clearly demonstrated; no marjoram-specific data found. Preparation or compound: Essential oils in general |
11 |
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Anxiety and stress scores (STAI, visual scales, WHO-5) | Biological association | Very low certainty | Measured in trials: decrease (anxiety, stress); increase (WHO-5 well-being). A lab change is not the same as a health benefit. | 10 1 9 2 |
| Heart rate and mean arterial pressure | Biological association | Low certainty | Measured in trials: no change expected. A lab change is not the same as a health benefit. | 10 |
| Menstrual pain scores (numeric, verbal and visual scales) | Biological association | Very low certainty | Measured in trials: decrease. A lab change is not the same as a health benefit. | 12 8 |
| Lymphocyte counts (CD8+, CD16+, CD4+/CD8+ ratio) | Biological association | Not enough evidence | Measured in trials: mixed. A lab change is not the same as a health benefit. | 9 |
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Terpinen-4-ol | Biological association | Laboratory | Slowed bacterial growth and biofilm in test tubes. No effect in people was read. Preparation or compound: Essential oil |
19 7 6 13 14 |
| Sabinene | Biological association | Laboratory | In a laboratory test it blocked a bacterial efflux pump in a sensitive E. coli strain and slowed biofilm. No effect in people was read. Preparation or compound: Essential oil |
19 7 14 |
| trans-Sabinene hydrate | Biological association | Laboratory | Listed among the largest components in two oils; the sabinene hydrate form slowed biofilm in the test tube. The PubChem CID was not checked. Preparation or compound: Essential oil |
7 6 |
| Linalyl acetate | Biological association | Laboratory | A component of that oil; its own activity was not described in the abstract. Preparation or compound: Essential oil |
6 |
Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 25, 2026).
Evidence at a glance: what changed in 1 lab markers
Tap a number to show only those markers. Counts are markers, not people.
The evidence
The research centre for Sweet Marjoram Oil. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
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 15 PubMed papers, the Poison Control and Pet Poison Helpline pages, and checked the plant name in GBIF and two compounds in PubChem. We did not find or read a LiverTox, LactMed, IFRA or FDA statement.
Study library: every study we checked 19
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Anne-Florence 2026 The Efficacy of Aromatherapy on Well-Being and Stress Nurs Crit Care · PMID 41330862 · DOI |
Randomized open label crossover trial |
49 Hospital staff in emergency, intensive care, anaesthesia and operating theatre departments (France) |
A four-oil mixture (sweet orange, lavender, marjoram, ylang ylang), inhaled from a stick Not reported here 2 months · vs a 2-month period with no essential oils |
WHO-5 well-being was higher in the aromatherapy period than the control period (65.9 +/- 1.8 vs 60.4 +/- 1.8, p = 0.0142). General anxiety and perceived stress scores were also significantly lower. WHO-5: 65.9 vs 60.4 (least-square means) Methods, limits and fundingOutcomes: WHO-5 well-being index (primary), anxiety and perceived stress scores Limitations: A four-oil mixture, so nothing can be credited to marjoram. Open-label (no blinding, no inert comparison), self-rated outcomes, one hospital. 51 were randomised and 49 analysed. Funding and conflicts: Funded by the hospital group that ran the study (Groupement Hospitalier Regional Mulhouse Sud Alsace). Registered: NCT05373849. Read: abstract |
| Avci 2026 Effects of Aromatherapy on Stress and Anxiety Among Intensive Care Unit Nurses: A Systematic Review Nurs Crit Care · PMID 42786785 · DOI |
Systematic review |
5 ICU nurses (five studies, 254 participants: two randomised trials and three quasi-experimental studies) |
Various essential oils and application methods (inhalation, topical) · vs various |
Aromatherapy may reduce stress among ICU nurses; evidence for less anxiety is mixed and less consistent across studies. Further high-quality studies are needed before firm conclusions or routine clinical use. Not given in the abstract Methods, limits and fundingOutcomes: Stress and anxiety Limitations: Few, mixed studies of many different oils. Not specific to marjoram. Only the abstract was read. Funding and conflicts: Authors declared no conflicts of interest. Read: abstract |
| Benito 1996 Labiatae allergy: systemic reactions due to ingestion of oregano and thyme Ann Allergy Asthma Immunol · PMID 8630713 · DOI |
Case report |
1 One patient with three systemic allergic reactions to oregano and thyme, and ten controls |
Oregano and thyme (eaten); skin tests with dried plants and extracts from the mint family herb · vs ten control patients |
Skin-prick tests to mint-family plants were positive in the patient and not in controls, and specific IgE was found to all herbs tested. The authors conclude that plants of the mint (Labiatae) family seem to show cross-sensitivity. The abstract lists marjoram among the family's plants but does not say that marjoram itself was tested. Methods, limits and fundingOutcomes: Skin tests and specific IgE to mint-family plants Limitations: One patient, culinary herbs, not oils. Whether marjoram was part of the testing is not stated in the abstract. Funding and conflicts: Not stated in the abstract. Read: abstract |
| EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) 2025 Safety and efficacy of a feed additive consisting of an essential oil derived from the leaves of Origanum majorana L. (marjoram oil) for use in all animal species (FEFANA asbl) EFSA Journal · PMID 41394339 · DOI |
Regulatory scientific opinion animal feed opinion |
Animal species (feed additive); also user and consumer safety | Essential oil from the leaves of Origanum majorana L. leaf Not repeated here |
Use at the proposed feed level was very unlikely to cause adverse effects in long-living and reproductive animals and of no safety concern for animals raised for meat. No safety concern for consumers of animal products or for the environment. For users, the oil should be considered an irritant to skin and eyes and a dermal and respiratory sensitiser. Handling the oil may expose unprotected users to estragole, a genotoxic carcinogen. Exposure of users by any route is a risk and should be minimised. The leaves and their preparations are recognised to flavour food. Methods, limits and fundingOutcomes: Safety for animals, consumers, users and environment Limitations: A feed-additive opinion: the user-safety lines describe handling the concentrated oil, not home use. Only the PubMed abstract was read, not the full opinion. Funding and conflicts: EFSA panel opinion; the application came from the feed-additive trade body FEFANA. Read: abstract |
| Eisenreich 2021 Alkenylbenzenes in Foods: Aspects Impeding the Evaluation of Adverse Health Effects Foods · PMID 34574258 · DOI |
Narrative review n/a |
n/a (food chemistry and toxicology) | Alkenylbenzenes (safrole, methyleugenol, estragole) in herbs, spices and their oils |
Alkenylbenzenes occur in herbs and spices such as basil or fennel seeds, and essential oils are often high in them. Safrole and methyleugenol are known to be genotoxic and carcinogenic. The review discusses what is known and not known about their effect on human health, focusing on safrole, methyleugenol and estragole. Methods, limits and fundingOutcomes: Evidence on health effects of alkenylbenzenes in food Limitations: Does not mention marjoram in the abstract. Used only to explain what estragole is and why it is discussed; it does not measure risk from marjoram oil. Funding and conflicts: Authors declared no conflict of interest. Read: abstract |
| Elkousy 2022 GC/MS analysis and potential synergistic effect of mandarin and marjoram oils on Helicobacter pylori J Enzyme Inhib Med Chem · PMID 35642325 · DOI |
Laboratory study laboratory |
Mandarin leaf and marjoram herb oils tested against Helicobacter pylori in the laboratory | Marjoram herb essential oil, mandarin leaf oil, and the two combined herb · vs clarithromycin (reference) |
Marjoram oil was mainly trans-sabinene hydrate (36.11%), terpinen-4-ol (17.97%), linalyl acetate (9.18%) and caryophyllene oxide (8.25%). It slowed H. pylori in the test tube (MIC 11.40 ug/mL) more than mandarin oil, and the combined oil showed synergy. Docking and toxicity work was computer-based. Methods, limits and fundingOutcomes: Composition (GC/MS), minimum inhibitory concentration, computer docking Limitations: Test-tube and computer work. The authors' wording that the combination could be a candidate to manage H. pylori is a hope, not a result in people. Funding and conflicts: Authors declared no conflict of interest. Read: abstract |
| Ghazal 2022 Antimicrobial, Multidrug Resistance Reversal and Biofilm Formation Inhibitory Effect of Origanum majorana Extracts, Essential Oil and Monoterpenes Plants (Basel) · PMID 35684205 · DOI |
Laboratory study laboratory |
Marjoram essential oil and extracts tested on bacterial strains in the laboratory | Origanum majorana essential oil, hexane extract and single monoterpenes |
The essential oil's main constituents were trans-sabinene hydrate (25.18%), terpinen-4-ol (24.92%), gamma-terpinene (6.48%), cis-sabinene hydrate (5.44%), p-cymene (4.72%), sabinene (4.53%), alpha-terpineol (4.43%) and alpha-terpinene (3.00%). The oil and some single compounds slowed growth of sensitive and drug-resistant S. aureus and E. coli in the test tube; effects on biofilm differed by strain and by oil versus single compound. Methods, limits and fundingOutcomes: Composition (GC-MS), antibacterial, efflux pump and biofilm tests Limitations: Test-tube work only. Does not show any effect in people. Funding and conflicts: Public research grant (National Research, Development and Innovation Office); the authors declared no conflict of interest. Read: abstract |
| Hur 2012 Aromatherapy massage on the abdomen for alleviating menstrual pain in high school girls: a preliminary controlled clinical study Evid Based Complement Alternat Med · PMID 21949670 · DOI |
Preliminary controlled clinical study |
55 Korean high school girls with menstrual pain |
Abdominal massage with clary sage, marjoram, cinnamon, ginger and geranium in almond oil, given once Not reported here One massage; pain checked 24 hours later · vs acetaminophen (paracetamol) group |
Pain fell more in the aromatherapy massage group (n = 32) than in the acetaminophen group (n = 23). The authors say it could not be verified whether the benefit came from the aromatherapy, the massage, or both. Greater pain reduction than acetaminophen; no numbers in the abstract Methods, limits and fundingOutcomes: Menstrual pain on a visual analogue scale at baseline and 24 hours Limitations: A five-oil blend plus massage, one session, a small non-blinded comparison with a medicine. Cannot separate marjoram, the other oils and the massage. Only the abstract was read. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Kuriyama 2005 Immunological and Psychological Benefits of Aromatherapy Massage Evid Based Complement Alternat Med · PMID 15937558 · DOI |
Small preliminary comparison |
11 Recipients of carrier-oil massage and of aromatherapy massage (11 people) |
Massage with sweet almond oil plus lavender, cypress and sweet marjoram oils Not reported here · vs carrier-oil massage |
Anxiety (STAI) and depression (SDS) scores fell after both kinds of massage, with no difference between aromatherapy and carrier massage. Aromatherapy massage was followed by a significant increase in peripheral blood lymphocytes, with CD8+ and CD16+ lymphocytes up and the CD4+/CD8+ ratio down. The authors say findings need checking in a larger group. No difference in STAI or SDS between groups Methods, limits and fundingOutcomes: Blood cell counts, interferon-gamma, IL-6, salivary IgA, STAI anxiety and self-rating depression scores Limitations: Eleven people, a three-oil blend with massage, laboratory markers that are not health outcomes. The abstract calls the study preliminary. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Lee 2023 Inhalation of Origanum majorana L. essential oil while working reduces perceived stress and anxiety levels of nurses in a COVID-19 intensive care unit: a randomized controlled trial Front Psychiatry · PMID 38045619 · DOI |
Randomized controlled trial |
57 Nurses in one COVID-19 intensive care unit (Korea) |
3% Origanum majorana essential oil, inhaled for 2 hours while at work Not reported here 2 hours, one session · vs almond oil (control) |
MAP did not differ within or between groups. Heart rate rose significantly in the marjoram group (p = 0.031) but stayed in the normal range. There was no significant between-group difference in state anxiety or VAS-anxiety after the intervention. Within the marjoram group, state anxiety (p = 0.001), VAS-anxiety (p = 0.037) and VAS-stress (p = 0.026) were lower after than before. No between-group difference in anxiety; within-group falls only Methods, limits and fundingOutcomes: Mean arterial pressure, heart rate, state anxiety score, visual analogue scales (VAS) for anxiety and stress, before and after Limitations: One hospital unit, 57 nurses, one 2-hour session. The fair comparison (between groups) was not significant for anxiety, although the authors' conclusion is more positive. The smell of marjoram is hard to hide, so nurses probably knew which group they were in. The abstract does not report a between-group test for stress. Funding and conflicts: Authors declared no commercial or financial conflicts. Registered: KCT0007543. Read: abstract |
| Lis-Balchin 1999 Possible health and safety problems in the use of novel plant essential oils and extracts in aromatherapy J R Soc Promot Health · PMID 10673845 · DOI |
Narrative review n/a |
n/a | Essential oils in aromatherapy |
Most commonly used oils in massage are seldom dangerous, with low systemic toxicity, especially at 2% dilution if not adulterated, but safety in pregnancy, childbirth and babies has not been clearly demonstrated. Sensitisation is a growing concern. Some novel oils have no odour and are potentially toxic. Methods, limits and fundingOutcomes: Health and safety problems of aromatherapy oils Limitations: A 1999 review of essential oils in general; marjoram is not named in the abstract. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Ou 2012 Pain relief assessment by aromatic essential oil massage on outpatients with primary dysmenorrhea: a randomized, double-blind clinical trial J Obstet Gynaecol Res · PMID 22435409 · DOI |
Randomized double blind trial |
48 Outpatients with primary dysmenorrhea diagnosed by a gynecologist, with pain above 5 on a 10-point scale (Taiwan) |
Lavender, clary sage and marjoram essential oils blended 2:1:1, in unscented cream at 3%, massaged on the lower abdomen daily 3% blend (a trial setting, not advice) From the end of one period to the start of the next (one cycle) · vs unscented cream with synthetic fragrance |
Both pain scales fell significantly (P < 0.001) in both groups after one cycle. Pain duration fell from 2.4 to 1.8 days in the essential oil group. The authors say four analgesic-type components made up 79.29% of the blend (linalyl acetate, linalool, eucalyptol, beta-caryophyllene). Both groups improved; duration 2.4 to 1.8 days in the oil group Methods, limits and fundingOutcomes: Numeric and verbal pain rating scales; duration of pain Limitations: A three-oil blend, so nothing can be credited to marjoram. The fragrance-only group improved as well, and the abstract gives no between-group test. Part of the change is likely massage, expectation or time. Only the abstract was read. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Paudel 2022 Chemical Composition, Enantiomeric Distribution, Antimicrobial and Antioxidant Activities of Origanum majorana L. Essential Oil from Nepal Molecules · PMID 36144869 · DOI |
Laboratory study laboratory |
2 Two marjoram oil samples from Kathmandu and Bhaktapur, Nepal |
Marjoram essential oil, hydro-distilled · vs standards |
50 and 41 compounds were found in the two samples. Oxygenated monoterpenoids, along with terpinen-4-ol, were predominant in both, with some variation in major components. Clustering of 50 published compositions showed at least 5 different chemotypes of marjoram oil. Antioxidant activity of one sample was moderate; its MIC of 78.1 ug/mL was effective against Aspergillus niger and Candida albicans in the test tube. Methods, limits and fundingOutcomes: Composition (GC-MS), enantiomers, antioxidant and antimicrobial tests Limitations: Laboratory work on two samples. Test-tube activity does not show an effect in people. Funding and conflicts: Authors declared no conflict of interest. Read: abstract |
| Sarfaraz 2023 Essential Oil Composition and Antioxidant Activity of Oregano and Marjoram as Affected by Different Light-Emitting Diodes Molecules · PMID 37175125 · DOI |
Laboratory and growing study laboratory |
Oregano and marjoram plants grown under different LED light | Essential oils of oregano and marjoram · vs ambient light control |
GC-MS found thymol, terpinen-4-ol, sabinene, linalool, p-cymene and gamma-terpinene as the main compounds across oregano and marjoram. Thymol in marjoram varied from 17.47% to 35.06% between samples. Light colour changed the profile. Methods, limits and fundingOutcomes: Essential oil content and composition, phenolics, antioxidant capacity Limitations: Plant-growing and laboratory work. Shows how much composition can vary, not anything about use in people. The thymol range is for these grown samples and may reflect the plant material tested. Funding and conflicts: Public grant (Polish National Agency for Academic Exchange); the authors declared no conflict of interest. Read: abstract |
| Walker S (veterinary student extern 2026 Pet Poison Helpline: Essential Oils (page read 2026-10-25) n/a · Source |
Animal poison centre education page pets |
n/a | n/a |
Essential oil poisoning can affect all species, but cats and birds are at the greatest risk. Common signs are drooling, vomiting, lethargy, loss of appetite, and irritation of skin, airways and mucous membranes. Signs usually appear within 6 to 8 hours. Oral exposure carries the highest risk, then skin, then breathing. Its list of oils that can cause poisoning does not include marjoram; that is not proof that marjoram is safe for pets. Do not make a pet vomit. Call a veterinarian or the helpline. Methods, limits and fundingOutcomes: Essential oil poisoning in pets, in general Limitations: Not specific to marjoram; a long list of oils is given and marjoram is not named. Read: full-text |
| de Groot 2016 Essential Oils, Part IV: Contact Allergy Dermatitis · PMID 27427818 · DOI |
Narrative review |
Patients patch-tested for suspected contact dermatitis, and case reports | Essential oils in general |
Nearly 80 essential oils have caused contact allergy. Nine tested in consecutive patients gave over 2% positive patch tests (laurel, turpentine, orange, tea tree, citronella, ylang-ylang, sandalwood, clove, costus root). Most reactions come from pure oils or high-concentration products. Massage professionals may develop occupational contact dermatitis. Reacting to one oil and to fragrance mix together is frequent. Patients should preferably be tested with their own products. Methods, limits and fundingOutcomes: Contact allergy to essential oils Limitations: The abstract does not name marjoram. It is a review of essential oils in general, so it shows the kind of risk, not a rate for marjoram oil. Funding and conflicts: Not stated in the abstract. Read: abstract |
| n/a 2026 Poison Control (National Capital Poison Center): Essential oils: Poisonous when misused (page read 2026-10-25) n/a · Source |
Poison centre education page n/a |
n/a | n/a |
General essential-oil page, not about marjoram. Says misuse can cause serious poisoning; many oils can cause rashes and some are poisonous if absorbed through the skin or swallowed; aspirating an oil into the lungs can cause pneumonia; children have thin skin and immature livers and may be more susceptible; oils may interact with medications; it can be hard to know the species, concentration or contaminants in a bottle; diluting in a carrier oil is the best way to avoid a bad skin reaction and oils should not be used on damaged skin; oils at home must be locked out of sight and reach of children and pets (or discarded if young children are in the home); the most common allergic reaction is a skin rash, and use should stop if one occurs. Describes a toddler who swallowed a small amount of lavender extract and became extremely drowsy and confused for several hours. Gives no marjoram case. Methods, limits and fundingOutcomes: Safety statements for essential oils in general Limitations: Not specific to marjoram. Read: full-text |
| n/a 2026 GBIF Backbone Taxonomy: Origanum majorana L. (match API read 2026-10-25) n/a · Source |
Registry or database n/a |
n/a | n/a |
Accepted species name Origanum majorana L., rank species, status ACCEPTED, family Lamiaceae, order Lamiales, genus Origanum, species key 2926615, match confidence 99. Methods, limits and fundingOutcomes: Accepted name and family Read: full-text |
| n/a 2026 PubChem compound records: terpinen-4-ol (CID 11230) and sabinene (CID 18818), read 2026-10-25 n/a · Source |
Registry or database n/a |
n/a | n/a |
Terpinen-4-ol: CID 11230, formula C10H18O, 4-methyl-1-propan-2-ylcyclohex-3-en-1-ol. Sabinene: CID 18818, formula C10H16. Methods, limits and fundingOutcomes: Compound identity Read: full-text |
What we do not know yet
- What the evidence supports: stress and period pain are very-low certainty; the only trial of marjoram alone showed no clear anxiety benefit between groups.
- No trial of marjoram oil alone for period pain, sleep, constipation or digestion was found.
- No patch-test rate, asthma data or sun-sensitivity data for marjoram oil were found.
- No study of marjoram oil in pregnancy, breastfeeding, children or pets.
- No LiverTox, LactMed, IFRA, SCCS, FDA, NCCIH or EMA statement was read.
How new research is added
New studies are found by a saved PubMed search and are placed in a review queue. A person reads each one before it is added.
Lab markers
What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".
Other 4
Anxiety and stress scores (STAI, visual scales, WHO-5)
Decrease (anxiety, stress); increase (WHO-5 well-being) in trials
Self-rated numbers for how anxious, stressed or well someone feels.
Very low certaintyResults and what it means
Why it was measured
The main outcomes in the nurse and staff studies.
Statistical vs. clinical meaning
Self-rated and open to expectation; a fall in both groups means much of the change is not from the oil.
Safety implication
A lower score does not show the oil is safe or helps an anxiety disorder.
| Study | Result | People | Product |
|---|---|---|---|
| 10 | No significant difference between marjoram and almond oil in anxiety; lower than before within the marjoram group. | ||
| 1 | Well-being higher and anxiety and stress lower in the mixture period than in the no-oil period (open-label). | ||
| 9 | Anxiety and depression fell with both aromatherapy and carrier-oil massage, with no difference. |
Heart rate and mean arterial pressure
No change expected in trials
Pulse, and average blood pressure over a heartbeat.
Low certaintyResults and what it means
Why it was measured
Physical stress markers in the ICU nurse trial.
Statistical vs. clinical meaning
A small rise in pulse; the authors say it was not clinically meaningful.
Safety implication
None shown at this level, from one 2-hour session.
| Study | Result | People | Product |
|---|---|---|---|
| 10 | Mean arterial pressure did not change. Heart rate rose slightly in the marjoram group after 2 hours (p = 0.031) but stayed within the normal range. |
Menstrual pain scores (numeric, verbal and visual scales)
Decrease in trials
Self-rated pain, and the number of days it lasts.
Very low certaintyResults and what it means
Why it was measured
Main outcome in both period-pain trials.
Statistical vs. clinical meaning
Self-rated, with blends and massage; improvement in the fragrance-only group means much is not from the oils.
Safety implication
A lower score does not mean the cause of the pain is gone.
Lymphocyte counts (CD8+, CD16+, CD4+/CD8+ ratio)
Mixed results in trials
Counts of certain white blood cells.
Not enough evidenceResults and what it means
Why it was measured
Immune markers in the 11-person massage study.
Statistical vs. clinical meaning
A lab marker whose meaning for health was not shown.
Safety implication
None.
| Study | Result | People | Product |
|---|---|---|---|
| 9 | CD8+ and CD16+ lymphocytes rose and the CD4+/CD8+ ratio fell after aromatherapy massage, not after carrier massage. |
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 6
- Skin, eyes and breathing: EFSA says treat marjoram oil as an irritant and a sensitiser.. EFSA's feed-additive panel says the marjoram oil it assessed (from the leaves of Origanum majorana) should be considered an irritant to skin and eyes and a skin and respiratory sensitiser for people who handle it. A review of essential oils and contact allergy says nearly 80 oils have caused allergy, that most reactions follow pure oils or high-concentration products, and that massage professionals can develop occupational dermatitis. That review's abstract does not name marjoram, and we found no patch-test rate for marjoram oil. Poison Control says the most common allergic reaction to essential oils is a skin rash: stop and wash the oil off. A person allergic to one oil, or to fragrance mix, is often allergic to others. Authoritative guidance 4 16 17
- Do not swallow essential oil. No marjoram-specific poisoning case was found, but poison centres warn about all concentrated oils.. Poison Control says some essential oils are poisonous if swallowed or absorbed through the skin, and that oil that goes into the lungs can cause pneumonia. It describes a toddler who became extremely drowsy and confused after swallowing a small amount of lavender extract. Marjoram oil is not named on that page, and we found no case report or toxic amount for it. This page gives no amount and no swallowing advice. If an oil may have been swallowed, call poison control (US: 1-800-222-1222) or your local emergency number. Authoritative guidance 17
- Estragole: EFSA names it as a risk for people who handle the concentrated oil.. EFSA says that when handling the marjoram oil it assessed, unprotected users may be exposed to estragole, a genotoxic carcinogen, and that exposure of users by any route is a risk and should be minimised. This is handler wording from an animal-feed opinion. It is not a measurement of risk from occasional home use, and oils vary. A review of alkenylbenzenes in food explains why this family of compounds (estragole, safrole, methyleugenol) is watched. We found no composition figure for estragole in marjoram oils in the sources read. Authoritative guidance 4 5
- Keep the oil away from children and pets.. Poison Control says children have thin skin and immature livers and may be more susceptible to toxic effects, and that oils at home must be locked out of sight and reach of children and pets (or discarded if young children are in the home). Pet Poison Helpline says cats and birds are at the greatest risk of essential oil poisoning; its list of oils that can cause poisoning does not name marjoram, which is not proof that it is safe. We found no study of marjoram oil in children or pets. Authoritative guidance 17 15
- Pregnancy and breastfeeding: not shown to be safe.. A 1999 review says the safety of aromatherapy oils in pregnancy, childbirth and babies has not been clearly demonstrated. We found no study of marjoram oil in pregnancy or breastfeeding, and no source we read that tests the common online claim that marjoram brings on periods. Not having data is not proof of safety. Ask a midwife or doctor before using any essential oil. Narrative review 11
- Marjoram is in the mint family, and mint-family allergy can cross over.. A case report of one person with serious allergic reactions to eaten oregano and thyme found cross-sensitivity across mint-family (Labiatae) plants on skin tests. Its abstract lists marjoram as a member of the family but does not say marjoram was tested. This was a single case with culinary herbs, not oils. Case report 3
Side effects 5
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| Skin irritation and allergic skin reaction (contact dermatitis) EFSA classes the assessed oil as a skin and eye irritant and a dermal sensitiser for handlers. The contact-allergy review covers essential oils in general and does not name marjoram in its abstract. | No rate found for marjoram oil | Not graded for marjoram oil Usually settles when exposure stops (Poison Control says stop and wash off); the allergy itself can persist (inference from how contact allergy works; not stated in the abstracts) | Authoritative guidance 4 16 17 |
| Breathing-related sensitisation EFSA says the oil should be considered a respiratory sensitiser for users. No source we read gives asthma data for diffusing marjoram oil at home. | Not given | Not given Not given | Authoritative guidance 4 |
| Cross-reaction with other oils, fragrances and mint-family plants A single case report links mint-family herbs. Not shown specifically for marjoram oil. | Co-reactivity with other essential oils and fragrance mix is described as frequent for oils in general | Not stated Not stated | Narrative review 16 3 |
| Slightly faster heart rate after 2 hours of inhaling 3% marjoram oil Short, single session. | One trial of 57 nurses (p = 0.031) | Within the normal range; the authors say not clinically meaningful Not followed up | RCT 10 |
| Headache, nausea, dizziness, drowsiness The trial abstracts do not report these. Absence of a report is not proof of absence. | Not described in the sources read | n/a n/a | Insufficient 10 12 |
Liver
No liver injury linked to marjoram oil was described in the sources we read. LiverTox was not checked for this oil. EFSA names estragole as a genotoxic carcinogen for unprotected handlers; that statement is about handling, not a report of liver harm. Poison Control gives swallowed pennyroyal oil as an example of liver poisoning and says children's livers are immature; it does not name marjoram. 4 17
How often. Not established.
This is a safety connection. It is not evidence that Sweet Marjoram Oil supports liver health.
Medicines and supplements 3
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Other essential oils, fragrance mix and mint-family plants (for example oregano, thyme) allergy | Co-reactivity is described as frequent among essential oils and fragrance mix; one case report found cross-sensitivity across mint-family plants. | If you have reacted to a perfume or oil, you may react to others. Not measured for marjoram oil. | Narrative review Low certainty 16 3 | If you have reacted to a perfume or an essential oil, tell a pharmacist or dermatologist before trying another. |
| Prescription and over-the-counter medicines in general unknown | Poison Control says essential oils may interact with medications. | General statement; no marjoram-specific interaction was found in the sources read. | Authoritative guidance Not enough evidence 17 | Ask a pharmacist. |
| Other skin creams or medicated products applied to the same skin skin-products | Not studied. | No source read addresses this. | Insufficient Not enough evidence | Ask a pharmacist if you use medicated skin products. |
Who should check first 5
| Situation | Advice | Evidence |
|---|---|---|
| Known allergy to marjoram, oregano, mint-family herbs, fragrances or essential oils; a history of reacting to perfumes | Avoid. Cross-reactions are described among essential oils and mint-family plants. | Narrative review 16 3 |
| Swallowing essential oil, especially by or near children | Do not swallow. If a child or pet may have swallowed any essential oil, call poison control (US: 1-800-222-1222) or your emergency number. | Authoritative guidance 17 |
| Pregnancy or breastfeeding | Safety is not established. Ask a midwife or doctor before using essential oils. | Narrative review 11 |
| Broken or damaged skin | Poison Control says do not use essential oils on damaged skin. | Authoritative guidance 17 |
| Asthma or scent sensitivity | EFSA calls the oil a respiratory sensitiser for handlers. No home-diffusing data were found, so ask a doctor or pharmacist. | Authoritative guidance 4 |
Overdose, product quality and regulators
Summary. No lethal or toxic amount for marjoram oil is described in the sources we read, and none is stated here. Poison centres warn about essential oils in general.
Amounts. No safe amount is established, and this page gives none.
Onset and course. Not described for marjoram oil.
Repeated use. Repeated skin exposure is the route linked to allergy in oils generally; massage professionals can develop occupational dermatitis.
Animal data. EFSA's feed opinion found the oil very unlikely to cause adverse effects in long-living and reproductive animals at the proposed feed level, and of no safety concern for animals raised for meat. That is about food additives, not diffusers or skin products. Pet Poison Helpline says cats and birds are at greatest risk from essential oils in general and does not name marjoram.
Toxic parts. The oil is a concentrate from the leaves (EFSA). Which components cause the allergy was not described in the abstracts read. Estragole is named by EFSA as a handler concern.
Not read. The full EFSA opinion, IFRA and EU cosmetic allergen lists, Tisserand safety data, LiverTox, LactMed and veterinary papers were not read.
What is in a bottle can differ from the label, and marjoram oil itself varies a lot.
Unknown species, strength and contaminants. Poison Control says essential oil products are not well regulated and it can be hard to know the species, concentration or contaminants in a bottle. 17
Composition varies. A study of two Nepalese samples and 50 published compositions found at least 5 different chemotypes of marjoram oil. A growing study found thymol in marjoram samples ranged from 17.47% to 35.06% and that light colour changed the profile. Two other analyses found different leading compounds (trans-sabinene hydrate at about 36% and 25% in two oils, terpinen-4-ol at about 18% and 25%). 13 14 7 6
Different plants sold as marjoram. This page is about oil from Origanum majorana. Oregano oils are different products with their own main compounds; in the light study oregano and marjoram both listed thymol among main compounds, in different amounts. A source that tests how often bottles are mislabelled was not read, so no rate is given. 14
| Body | Action | Date |
|---|---|---|
| European Food Safety Authority (EFSA), FEEDAP Panel (European Union) | 2025 opinion on marjoram oil from Origanum majorana leaves as a feed additive: very unlikely to cause adverse effects at the proposed feed level; no concern for consumers or the environment; the oil should be considered an irritant to skin and eyes and a dermal and respiratory sensitiser; unprotected users may be exposed to estragole, a genotoxic carcinogen, and user exposure should be minimised. source | 2025-12 |
| Poison Control (National Capital Poison Center) (United States) | General warnings on essential oils: poisoning if swallowed or absorbed, pneumonia if aspirated, rash and allergy, children and pets, possible medicine interactions. source | 2026-10-25 |
| Pet Poison Helpline (United States) | General warnings on essential oil poisoning in pets: cats and birds at greatest risk; marjoram not named in its list. source | 2026-10-25 |
When to get medical help
- If a child or pet may have swallowed any essential oil, call poison control (US: 1-800-222-1222) or your local emergency number right away. For a pet, call a vet or an animal poison helpline.
- Swelling of the face or throat, trouble breathing, or a spreading rash after contact with an oil needs urgent medical care.
- Choking or coughing after oil is swallowed can mean it has entered the lungs: seek emergency care.
- A rash that appears after use: stop, wash the oil off, and see a doctor if it does not clear.
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 sweet marjoram oil safe to swallow?
No. Do not swallow essential oil. Poison Control warns that some oils are poisonous if swallowed and that oil entering the lungs can cause pneumonia. We found no marjoram case, and no safe amount is known. If a child or pet may have swallowed any essential oil, call poison control (US: 1-800-222-1222) or your emergency number.
Can marjoram oil cause skin or breathing problems?
Does marjoram oil help with stress or anxiety?
Does marjoram oil help period pain?
Does marjoram oil help with constipation, sleep or muscle pain?
Is marjoram oil safe in pregnancy or breastfeeding?
Not shown to be safe. A 1999 review says safety of aromatherapy oils in pregnancy has not been clearly demonstrated. We found no study of marjoram oil in pregnancy or breastfeeding, and none that tests online claims about marjoram and periods. Ask your midwife or doctor.
Is marjoram oil safe for children?
Ask a children's doctor first. Poison Control says children have thin skin and immature livers and may be more susceptible. We found no study of marjoram oil in children. Keep bottles out of reach.
Is marjoram oil safe for cats and dogs?
What is estragole and why does EFSA mention it?
Does marjoram oil interact with medicines?
No marjoram-specific interaction was found in the sources we read. Poison Control says essential oils in general may interact with medications, so ask a pharmacist.
What is in marjoram oil, and are all bottles the same?
No. Papers name terpinen-4-ol, sabinene, trans-sabinene hydrate and linalyl acetate among its compounds, but researchers found at least 5 chemotypes, and the leading compound differed between oils. Poison Control says it can be hard to know what species, strength or contaminants are in a bottle.
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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 15 PubMed papers, the Poison Control and Pet Poison Helpline pages, and checked the plant name in GBIF and two compounds in PubChem. We did not find or read a LiverTox, LactMed, IFRA or FDA statement.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
- No product is promoted on this page. No affiliate links are shown. Industry or hospital funding is labelled where the abstract gave it.
Sources 19
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Anne-Florence D, Samuel D, Cindy P, et al. The Efficacy of Aromatherapy on Well-Being and Stress. Nurs Crit Care. 2026. PMID 41330862. DOI 10.1111/nicc.70270. (abstract)
- Avci A, Avci M. Effects of Aromatherapy on Stress and Anxiety Among Intensive Care Unit Nurses: A Systematic Review. Nurs Crit Care. 2026. PMID 42786785. DOI 10.1111/nicc.70705. (abstract)
- Benito M, Jorro G, Morales C, Pelaez A. Labiatae allergy: systemic reactions due to ingestion of oregano and thyme. Ann Allergy Asthma Immunol. 1996. PMID 8630713. DOI 10.1016/S1081-1206(10)63456-4. (abstract)
- EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP). Safety and efficacy of a feed additive consisting of an essential oil derived from the leaves of Origanum majorana L. (marjoram oil) for use in all animal species (FEFANA asbl). EFSA Journal. 2025. PMID 41394339. DOI 10.2903/j.efsa.2025.9786. (abstract)
- Eisenreich A, Gotz ME, Sachse B, Monien BH. Alkenylbenzenes in Foods: Aspects Impeding the Evaluation of Adverse Health Effects. Foods. 2021. PMID 34574258. DOI 10.3390/foods10092139. (abstract)
- Elkousy RH, et al. GC/MS analysis and potential synergistic effect of mandarin and marjoram oils on Helicobacter pylori. J Enzyme Inhib Med Chem. 2022. PMID 35642325. DOI 10.1080/14756366.2022.2081846. (abstract)
- Ghazal TSA, et al. Antimicrobial, Multidrug Resistance Reversal and Biofilm Formation Inhibitory Effect of Origanum majorana Extracts, Essential Oil and Monoterpenes. Plants (Basel). 2022. PMID 35684205. DOI 10.3390/plants11111432. (abstract)
- Hur MH, Lee MS, Seong KY, Lee MK. Aromatherapy massage on the abdomen for alleviating menstrual pain in high school girls: a preliminary controlled clinical study. Evid Based Complement Alternat Med. 2012. PMID 21949670. DOI 10.1155/2012/187163. (abstract)
- Kuriyama H, Watanabe S, Nakaya T, et al. Immunological and Psychological Benefits of Aromatherapy Massage. Evid Based Complement Alternat Med. 2005. PMID 15937558. DOI 10.1093/ecam/neh087. (abstract)
- Lee SW, Shin YK, Lee JM, et al. Inhalation of Origanum majorana L. essential oil while working reduces perceived stress and anxiety levels of nurses in a COVID-19 intensive care unit: a randomized controlled trial. Front Psychiatry. 2023. PMID 38045619. DOI 10.3389/fpsyt.2023.1287282. (abstract)
- Lis-Balchin M. Possible health and safety problems in the use of novel plant essential oils and extracts in aromatherapy. J R Soc Promot Health. 1999. PMID 10673845. DOI 10.1177/146642409911900407. (abstract)
- Ou MC, Hsu TF, Lai AC, et al. Pain relief assessment by aromatic essential oil massage on outpatients with primary dysmenorrhea: a randomized, double-blind clinical trial. J Obstet Gynaecol Res. 2012. PMID 22435409. DOI 10.1111/j.1447-0756.2011.01802.x. (abstract)
- Paudel PN, Satyal P, Satyal R, Setzer WN. Chemical Composition, Enantiomeric Distribution, Antimicrobial and Antioxidant Activities of Origanum majorana L. Essential Oil from Nepal. Molecules. 2022. PMID 36144869. DOI 10.3390/molecules27186136. (abstract)
- Sarfaraz D, et al. Essential Oil Composition and Antioxidant Activity of Oregano and Marjoram as Affected by Different Light-Emitting Diodes. Molecules. 2023. PMID 37175125. DOI 10.3390/molecules28093714. (abstract)
- Walker S (veterinary student extern, University of Minnesota). Pet Poison Helpline: Essential Oils (page read 2026-10-25). n/a. 2026. (full-text)
- de Groot AC, Schmidt E. Essential Oils, Part IV: Contact Allergy. Dermatitis. 2016. PMID 27427818. DOI 10.1097/DER.0000000000000197. (abstract)
- n/a. Poison Control (National Capital Poison Center): Essential oils: Poisonous when misused (page read 2026-10-25). n/a. 2026. (full-text)
- n/a. GBIF Backbone Taxonomy: Origanum majorana L. (match API read 2026-10-25). n/a. 2026. (full-text)
- n/a. PubChem compound records: terpinen-4-ol (CID 11230) and sabinene (CID 18818), read 2026-10-25. n/a. 2026. (full-text)
Where to buy
Check the label first. Whatever you buy, look for these:
- The botanical (Latin) name on the label and 100% pure oil
- A dark glass bottle and a batch number
- Essential oils are strong: dilute for skin, and do not swallow unless a qualified professional directs it
- Keep away from children and pets
Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.
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