Tea tree oil
Australian tea tree; melaleuca oil, the name approved in Australia, and the older ‘ti tree oil’; Melaleuca alternifolia (Maiden and Betch) Cheel, with M. linariifolia Smith and M. dissitiflora F. Mueller; in pharmacy Melaleucae aetheroleum
- Known today as
- The essential oil steam-distilled from the leaves and end branchlets of Melaleuca alternifolia, a tree of the family Myrtaceae, which the European Medicines Agency’s assessment report says was named tea tree “because the leaves were used to prepare an aromatic tea.” Before it was cultivated its natural range was limited to the country around the Clarence and Richmond Rivers on the north-eastern coast of New South Wales; the oil now comes mainly from large plantations in New South Wales and Queensland. It is a clear, colourless or pale yellow liquid with “a distinct pleasant odour like turpentine,” about 2 per cent of the leaf.
- Kind
- Plant
- Constituents
- terpinen-4-ol, 1,8-cineole
- In other databases
- Plants of the World Online · GBIF · Wikidata
Caution. Not to be swallowed or inhaled, nor used in the eyes or ears, nor under twelve, nor by anyone allergic to it or to colophony. Stop if a rash develops. Smarting, itching, burning, redness, and contact dermatitis have been reported, and rarely burn-like reactions of the skin; the 2023 review found side effects minor except where the oil was applied at 25 per cent or more. Accidental ingestion can cause depression of the central nervous system and muscle weakness, and in children, the European agency warns, swallowing tea tree oil “is a medical emergency requiring immediate hospital treatment and respiratory support.”
Tea tree oil: what was it used for?
An antiseptic for the skin and mouth. The assessment report, following Carson and Riley, records its use by “Australian Bundjabung Aborigines” for several millennia for bruises, insect bites, and skin infections, and that it was rediscovered in the 1920s as a topical antiseptic “with more effective activity than phenol,” becoming a standard antiseptic for surgery, especially dental surgery. The British Pharmaceutical Codex of 1949 gave it as germicidal, applied to furunculosis, tinea, paronychia, impetigo, thrush, and stomatitis and inhaled in coryza; a 2023 review adds that First Nations Australians used the leaves for wounds, burns, and insect bites.
Tea tree oil: what does modern science say?
The European Medicines Agency’s herbal committee accepts the oil, for use on the skin and in the mouth only, as a traditional herbal medicine, “exclusively based upon long-standing use,” for small superficial wounds and insect bites, small boils and mild acne, the itching and irritation of mild athlete’s foot, and minor inflammation of the lining of the mouth (monograph of 2015). Its assessment report finds the oil made largely of cyclic monoterpenes, terpinen-4-ol chief among them at about 42 per cent in one analysis; the European Pharmacopoeia requires at least 30 per cent of terpinen-4-ol and at most 15 per cent of 1,8-cineole, which is probably an unwanted allergen. A 2023 review of forty-six randomised trials judged their quality poor to modest: mouthwashes may limit dental plaque, gels may aid the treatment of periodontitis, and topical regimens were about as effective as standard treatment in clearing MRSA from the body, but more evidence was needed for acne. A 2026 meta-analysis of seven acne studies found a modest reduction in severity. A Cochrane review of 2020 found the effect of 5 to 50 per cent tea tree oil on Demodex mites of the eyelids uncertain.
Pharmacognosy & Toxicology
- Constituents
- terpinen-4-ol ChEMBLchief of the cyclic monoterpenes, about 42 per cent in one analysis; at least 30 per cent required
- 1,8-cineole ChEMBLat most 15 per cent; probably an unwanted allergen
- Mechanism
- Not established in the sources read for this entry.
- Standing
- European Union herbal monograph (2015): traditional use on the skin and in the mouth, “exclusively based upon long-standing use,” for minor wounds, insect bites, mild acne, athlete’s foot, and mouth inflammation. Not to be swallowed.
- European Medicines Agency, Committee on Herbal Medicinal Products. European Union herbal monograph on Melaleucae aetheroleum (Tea-tree oil). EMA/HMPC/320930/2012, 24 November 2015. Read in full · the text read
- European Medicines Agency, Committee on Herbal Medicinal Products. Assessment report on Melaleucae aetheroleum. EMA/HMPC/320932/2012, 24 November 2014. Read in part · the text read
- Kairey L, et al. (2023). Efficacy and safety of <i>Melaleuca alternifolia</i> (tea tree) oil for human health-A systematic review of randomized controlled trials. Frontiers in pharmacology. PMID 37033604. Abstract read · the text read
- Savla K, et al. (2020). Tea tree oil for Demodex blepharitis. The Cochrane database of systematic reviews. PMID 32589270. Abstract read · the text read
The abstract of each source, beneath its citation. For Club members. About the Club or sign in.
Constituent names open the compound’s record at PubChem, and “ChEMBL” beside a name opens its record at ChEMBL, the European Bioinformatics Institute’s database of bioactive molecules. Where a mechanism line was checked against ChEMBL (ChEMBL 37, read 1 October 2026), the check is shown with the measured value and its source paper, or says plainly that nothing has been measured. Doses are as the references give them, for description only; this is not medical advice. Each source carries the result of its check against Crossref, PubMed, or the authority’s page: see Verification.
Tea tree oil: what lore surrounds it?
In veterinary practice, the 1949 Codex adds, it was used for mange and eczema and for sores and skin diseases of parasitic origin. The name ti tree, the assessment report notes, belongs properly to the Maori and Samoan name for plants of another genus, Cordyline.
Sources
- European Medicines Agency, Committee on Herbal Medicinal Products. European Union herbal monograph on Melaleucae aetheroleum (Tea-tree oil). EMA/HMPC/320930/2012, 24 November 2015. Read in full · the text read
- European Medicines Agency, Committee on Herbal Medicinal Products. Assessment report on Melaleucae aetheroleum. EMA/HMPC/320932/2012, 24 November 2014. Read in part · the text read
- Kairey L, et al. (2023). Efficacy and safety of <i>Melaleuca alternifolia</i> (tea tree) oil for human health-A systematic review of randomized controlled trials. Frontiers in pharmacology. PMID 37033604. Abstract read · the text read
- Ye Y, et al. (2026). Efficacy and Safety of Melaleuca alternifolia (Tea Tree) Oil for Acne-A Systematic Review and Meta-Analysis. Phytotherapy research : PTR. PMID 42098589. Abstract read · the text read
- Savla K, et al. (2020). Tea tree oil for Demodex blepharitis. The Cochrane database of systematic reviews. PMID 32589270. Abstract read · the text read
Verification
- Checked
- October 1, 2026
- Passes
- Every sentence read against its sources, in the pass over the remaining 343 entries
- The Standing line checked against the authority it names (EMA, WHO, FDA, CITES, Commission E)
- Every dated or regulatory claim checked by category across the database
- Sources
- 5 cited: 1 read in full, 1 read in part, 3 abstract read. 3 with the abstract on file.
- Corrections
- None were needed.
What was checked, how, and what was found is set out on the Verification page. A checked source is one whose record was found; it does not make the entry medical advice.
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Cite This Entry
Version 1 · first published October 16, 2026
- Chicago
“Tea tree oil.” In Materia Medica, edited by B. C. P. Statema. Version 1. The Thinking Press, 2026–. Last modified October 16, 2026. https://thethinkingpress.org/materia-medica/tea-tree-oil.
- MLA
“Tea tree oil.” Materia Medica, edited by B. C. P. Statema, version 1, The Thinking Press, 16 Oct. 2026, thethinkingpress.org/materia-medica/tea-tree-oil. Accessed 17 Oct. 2026.
- APA
Tea tree oil. (2026, October 16). In B. C. P. Statema (Ed.), Materia medica (Version 1). The Thinking Press. Retrieved October 17, 2026, from https://thethinkingpress.org/materia-medica/tea-tree-oil
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See Also
Sharing terpinen-4-ol, 1,8-cineole
Juniperus communis · Origanum majorana · Peumus boldus · Artemisia abrotanum · Elettaria cardamomum · Salvia rosmarinus
Nearby in the alphabet
Teasel (Dipsacus fullonum) · Tea (The dried leaves of Camellia sinensis) · Teonanácatl (Small mushrooms that turn blue where they are bruised) · Tansy (Tanacetum vulgare) · Terra sigillata (A clay dug on the island of Lemnos and stamped with a seal) · Tamarind (The pod pulp of Tamarindus indica) · Tetragrammaton (not pronounced in Jewish practice) · Sweet woodruff
Historical description, not medical advice.
