Eucalyptus oil
The trial evidence is for capsules of purified 1,8-cineole, the main component of eucalyptus oil: in two placebo-controlled trials they eased acute bronchitis and sinusitis symptoms within about 4 days.
The oil itself, inhaled for colds or rubbed on for muscle pain, rests on traditional use only, because the EU regulator found no clinical studies of the oil. It is dangerous if swallowed, especially for children, and must not be used near the face of a baby under 2.
At a glance
Last reviewed 10 October 2026What it's used for
Evidence is rated per use. The same ingredient can be strong for one thing and traditional for another.
| Use | Evidence | What the research shows |
|---|---|---|
| Acute bronchitis and acute sinusitis (cineole capsules, not the oil)Compare remedies for coughs & colds → | Moderate | In 242 people with acute bronchitis, 200 mg of cineole three times a day for 10 days improved the bronchitis symptom score more than placebo after 4 days (p = 0.038), with fewer cough fits (p = 0.0001). In 152 people with acute non-purulent rhinosinusitis, the same daily dose for 7 days cut a symptom score from 15.6 to 3.0, against 9.2 with placebo; two people reported mild heartburn or a rash. A 2025 systematic review of five capsule trials of essential-oil products in acute rhinosinusitis, including cineole, found symptom improvement in all of them and mostly mild stomach upset. The trials are two single studies of the same purified compound, not the raw essential oil, and we could not see who funded them.3,4,5 |
| Cough with a cold (inhaled eucalyptus oil) | Traditional | The EU regulator accepts eucalyptus oil for relief of cough associated with a cold on long-standing use alone and states that there are no clinical studies of the oil. The cineole capsule trials supported its assessment but were not treated as proof for the oil. See a doctor if the cough lasts more than a week, or if breathlessness, fever or purulent sputum appears.1,2 |
| Localised muscle pain (rubbed on the skin or in a bath)Compare remedies for joints and inflammation → | Traditional | The EU regulator lists eucalyptus oil for the symptomatic relief of localised muscle pain on traditional use only. It recommends seeing a doctor if the pain lasts more than 2 weeks of skin use, or if the area reddens or swells. We found no trial of eucalyptus oil for muscle pain.1,2 |
How much
Ranges below are what studies used and what supplements commonly contain. They are not a recommendation for you. Start at the low end.
How people take it
Safety
Who should avoid
- Swallowing the oil — as little as 5 mL of pure oil can cause severe poisoning
- Children under 2 — contraindicated by the EU regulator; risk of laryngospasm
- Children with a history of seizures — contraindicated by the EU regulator
- Pregnancy and breastfeeding — EU regulator: not recommended, safety not established
- Allergy to eucalyptus oil or 1,8-cineole — contraindicated; severe reactions are reported
- Broken or irritated skin, and near the eyes — do not apply
Known interactions
Questions people ask
What are the benefits of eucalyptus oil?
The best evidence is for purified cineole capsules, which eased acute bronchitis and sinusitis in two placebo-controlled trials. For the oil itself, the EU regulator accepts inhaling it for a cough with a cold and rubbing it on for muscle pain, but only on traditional use, because there are no clinical studies of the oil.
Is eucalyptus oil good for hair?
We found no human trials of eucalyptus oil for hair growth, dandruff or the scalp, so we cannot say it works. The regulator warns against applying it to broken or irritated skin, and contact eczema and allergic reactions are listed side effects, so dilute it and patch-test a small area if you try it.
What are the side effects and dangers of eucalyptus oil?
Swallowing is the main danger: a clinical guideline says as little as 5 mL of pure oil can cause severe symptoms, from drowsiness and seizures to coma, and there is no antidote.
In one Australian survey, most poisonings of young children came through a home vaporiser they could reach, and adults have had seizures too. On the skin, the EU regulator lists contact eczema and allergic reactions. If anyone swallows the oil, call your local poisons service or emergency number at once.
How do I use eucalyptus oil safely?
For colds, the EU traditional dose for adults is 3 to 8 drops in 250 ml of boiling water, inhaled three times a day, keeping the eyes out of the steam. For muscle aches, the regulator's strength is a 10% ointment. Keep it away from the face of babies under 2, do not use it in a child with a history of seizures, and store the bottle out of reach.
Sources (9)
- Regulator monograph European Medicines Agency HMPC. European Union herbal monograph on Eucalyptus globulus Labill.; Eucalyptus polybractea R.T. Baker; Eucalyptus smithii R.T. Baker, aetheroleum, Final - Revision 1 (EMA/HMPC/320292/2023). 2024.
- Regulator assessment report European Medicines Agency HMPC. Assessment report on Eucalyptus globulus Labill.; Eucalyptus polybractea R.T. Baker; Eucalyptus smithii R.T. Baker, aetheroleum, Final - Revision 1 (EMA/HMPC/320282/2023). 2024.
- Randomised controlled trial Fischer J, Dethlefsen U. Efficacy of cineole in patients suffering from acute bronchitis: a placebo-controlled double-blind trial. Cough. 2013.
- Randomised controlled trial Kehrl W, Sonnemann U, Dethlefsen U. Therapy for acute nonpurulent rhinosinusitis with cineole: results of a double-blind, randomized, placebo-controlled trial. Laryngoscope. 2004.
- Systematic review Matl CM, Jang W, Salley JR, Fort CL, Demke JC, Tran P, et al. Effects of Essential Oils in the Treatment of Acute Rhinosinusitis: A Systematic Review. Laryngoscope Investig Otolaryngol. 2025.
- Clinical guideline Royal Children's Hospital Melbourne. Clinical Practice Guidelines: Eucalyptus Oil Poisoning. Last updated July 2021.
- Poison-centre review Flaman Z, Pellechia-Clarke S, Bailey B, McGuigan M. Unintentional exposure of young children to camphor and eucalyptus oils. Paediatr Child Health. 2001.
- Poison-centre survey Day LM, Ozanne-Smith J, Parsons BJ, Dobbin M, Tibballs J. Eucalyptus oil poisoning among young children: mechanisms of access and the potential for prevention. Aust N Z J Public Health. 1997.
- Case reports Ittyachen AM, George GR, Radhakrishnan M, Joy Y. Eucalyptus oil poisoning: two case reports. J Med Case Rep. 2019.
Last reviewed 10 October 2026 · Next review April 2027 · How we rate evidence
Reader notes
Experiences and questions from readers, read by an editor before they appear. They are personal accounts, not evidence, and are not medical advice.