Tea Tree Oil
Tea tree oil (Melaleuca alternifolia): what it is, what NIH says about acne, athlete's foot and other uses, and why it must never be swallowed or used undiluted. Includes pet warnings.
Content last updated . This page has not been medically reviewed.
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Never swallow tea tree oil. Taken by mouth it can cause confusion, unsteadiness, inability to walk and coma. [1] Keep it away from children and pets. [2]
Overview
Tea tree oil comes from steam distillation of the leaves of the tea tree, a plant native to New South Wales and Queensland in Australia. Most is produced in Australia, with China and several African countries also producing it. The Aboriginal people of Australia traditionally used the leaves for treating wounds, burns and insect bites. Today the oil is promoted for external use for acne, athlete's foot, toenail fungus, lice and other conditions. [1]Names and plant
The plant is Melaleuca alternifolia. [1] GBIF accepts this name. [3] Other names include melaleuca oil and Australian tea tree oil. [1]What the research shows (NIH summary)
| Use | What NIH says | Strength of evidence |
|---|---|---|
| Acne | A small amount of research suggests it might help, but more evidence is needed [1] | Limited |
| Athlete's foot | A small amount of research suggests it may help, but may not work as well as standard treatments [1] | Limited |
| Fungal nail infections | Only a few studies; the amount and quality are insufficient for conclusions [1] | Insufficient |
| Head lice | Only evaluated in combination with other ingredients, so it is unclear what caused any effect [1] | Unclear |
| Eyelid inflammation from Demodex mites | Several studies; effectiveness is uncertain [1] | Uncertain |
| Gum inflammation, plaque, bad breath (mouthrinse) | Effectiveness is uncertain; mouthrinses should not be swallowed [1] | Uncertain |
NIH's overall summary: a small amount of evidence suggests topical tea tree oil might help acne and athlete's foot, more studies are needed, and for other conditions there is not enough evidence. [1]
Forms
Tea tree oil is used on the skin, in shampoos, creams and mouthrinses. We do not give a dilution amount. Concentration depends on the product, and the research does not give a universal rule. Follow the directions on a product made for the purpose, and ask a pharmacist or clinician about your situation.Safety
- Do not swallow it. Serious symptoms include confusion, unsteadiness, inability to walk and coma. [1]
- Skin. Most people can use topical products containing tea tree oil without problems, but some develop redness or irritation. This may be more likely if the product is old or has been exposed to heat, light or air. [1]
- Pregnancy and breastfeeding. NIH says topical products may be safe. [1] Ask your clinician.
- Hormone-related concern. NIEHS reports that laboratory tests found lavender and tea tree oil and some of their chemicals showed hormonal activity, and clinical cases linked skin use of essential oils with breast tissue growth in prepubescent boys. The lab work was done in test tubes, and more research is needed. [4] Ask a clinician if this concerns you for a child.
Pets
Pet Poison Helpline states that tea tree oil is toxic to pets at higher concentrations and that even a few concentrated drops applied to the skin or swallowed can cause severe poisoning. Pet products such as shampoos containing less than 1 to 2% are generally considered non-toxic when used as labeled. Signs include drooling, stumbling, weakness, tremor, coma, low body temperature, liver failure (reported in cats) and death. [2] Do not use tea tree oil on a pet unless a veterinarian tells you to. See Essential oils and pets for who to call.Quality
See the label guide. NIH notes older products, or those exposed to heat, light or air, may be more likely to cause skin reactions. [1]Frequently asked questions
Is tea tree oil safe to put on skin?
Most people tolerate topical products, but some develop redness or irritation. Do not use it undiluted, and never swallow it. [1]
Does tea tree oil work for acne?
A small amount of research suggests it might help, but more evidence is needed. [1]
Is tea tree oil safe for dogs and cats?
Not at higher concentrations. See the pets section above. [2]
References
- National Center for Complementary and Integrative Health (NIH). Tea Tree Oil: Usefulness and Safety. Page last updated April 2025.
- Pet Poison Helpline. Tea Tree Oil. Veterinary toxicology information; the page says it is not veterinary advice.
- GBIF Secretariat. GBIF Backbone Taxonomy. Names checked 2026-10-22 through the GBIF species match service.
- National Institute of Environmental Health Sciences (NIH). Essential Oils. Last reviewed March 19, 2026.
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.