Tea tree oil, extracted from the leaves of the Australian Melaleuca alternifolia tree, has been traditionally used to treat numerous ailments including skin problems (such as wounds, burns, athlete’s foot, acne, and dandruff), upper respiratory infections (like coughs, colds, and flu), sore throat, gum disease, halitosis, vaginitis, sprains, strains, and arthritic joints. Current research confirms its traditional use, finding that tea tree oil may have health benefits including wound-healing, immunomodulatory, anti-inflammatory, antiseptic, antibacterial, antiviral, and antifungal effects. [1-4] Commercially, tea tree oil has been used for decades in certain cosmetic, dental, and first aid formulations.
The majority of abovementioined uses concerning tree oil result from a potent bioactive compound called terpinin-4-ol. [4-5] Research suggests that tea tree oil may relieve inflammation and improve immunity by blocking the production of pro-inflammatory compounds prostaglandin E2 (PGE2) and tumor necrosis factor-alpha (TNF-alpha). [5-6] Research has also found that tea tree oil may inhibit a broad spectrum of viral, bacterial, yeast, and fungal infections. [1-4] Tea tree’s effectiveness is enhanced by its good penetration to the skin.
Volatile oil extracted from the leaves
Tea Tree Oil Uses
Tea tree may be used for its antiseptic capability on a broad spectrum of infectious organisms. Studies have shown that tea tree oil is effective for use as a topical antiseptic and skin disinfectant. [7-9] One study demonstrated therapeutic effects similar to those of five-percent benzoyl peroxide in acne patients when treated with a five-percent tea tree oil solution, but with fewer side effects.  Other studies suggest that tea tree oil may be effective against antibiotic-resistant Staphylococcus aureus coli and other bacteria such as Escherichia coli. [10-15]
Tea tree oil may be useful in treating vaginal infections, including those caused by yeast (Candida) and bacteria. [2-4, 16] Numerous studies have demonstrated tea tree oil’s antifungal effects against yeast such as Candida albicans. [17-20] Other studies have suggested that tea tree oil may help treat the fungi that cause athlete’s foot and nail disease. [20-23] One study found that tea tree oil may be as effective against toenail fungal infections (onychomycosis) as the antifungal drug clotrimazol. 
Tea tree oil may also be used to treat oral bacteria that cause cavities, gum disease, and halitosis. [4-24] Commercially, tea tree oil is considered an effective addition to antiseptic oral rinses and toothpastes.
Tea tree may speed the healing of wounds and burns. One study demonstrated therapeutic effects in partial thickness burns when treated with a tea tree hydrogel. 
- For topical application of pure essential oil, dilute 2 drops of tea tree essential oil in 2 tablespoons of vegetable oil. Apply to infected areas as needed. Discontinue use if tea tree oil irritates skin. [2-4]
- For oral application, dilute 2 drops of tea tree essential oil in 1 cup of water, swish in your mouth or gargle, then spit out. Do not swallow or take internally, as it can be poisonous.
Use gel, ointment, cream, and mouthwash as directed on the package instructions.
- Essential Oil (standardized extract at 30% terpinen-4-ol and 15% 1,8-cineol)
Tea tree should be used with caution for individuals prone to allergies. Some individuals may experience skin irritation (contact dermatitis) when tea tree is applied to the skin. Tea tree should be tested for sensitivity on a small area of the skin prior to use. Discontinue use if tea tree oil irritates skin. [2-3]
Tea tree oil can be poisonous if ingested. Contact a health care provider or poison control center immediately if tea tree is accidentally consumed. Tea tree oil should always be diluted when used as a preparation. Overdose may be possible with tea tree including signs of confusion, loss of consciousness, or coma. Contact emergency medical attention immediately if overdose is suspected.
Pregnant and lactating women and children should not use tea tree oil, unless recommended by a health care provider.
Although drug interactions with tea tree oil have not been reported, always inform your health care provider about the dietary supplements you are taking, since there may be a potential for side effects, interactions, or allergy.
1. Pizzorno JE and Murray MT, eds. Encyclopedia of Natural Medicine, revised 2nd edition, CA: Prima Publishing, 1998: 196.
2. Tea Tree Oil, Dietary Supplement Information Bureau: http://content.nhiondemand.com/dse/consumer/monoAll-style.asp?objID=100191&ctype=ds&mtyp=1
3. Tea Tree, PDR Health: http://www.pdrhealth.com/drug_info/nmdrugprofiles/herbaldrugs/101840.shtml
4. Duke J. The Green Pharmacy, New York: St. Martin’s Paperback, 1998: 184-185, 247-248, 265-266, 488, 536.
5. Hart PH, Brand C, Carson CF, et al. Terpinen-4-ol, the Main Component of the Essential Oil of Melaleuca alternifolia (Tea Tree Oil), Suppresses Inflammatory Mediator Production by Activated Human Monocytes. Inflamm Res. Nov2000;49(11):619-26.
6. Brand C et al. The water-soluble components of the essential oil of Melaleuca alternifolia (tea tree oil) suppress the production of superoxide by human moncyte, but not neutrophils, activated in vitro. Inflamm Res 2001 Apr;50(5):213-9.
7. Bassett IB, et al. A comparative study of tea-tree oil versus benzoylperoxide in the treatment of acne. Med J Aust. Oct1990;153(8):455-8.
8. Hammer KA et al. Susceptibility of transient and commensal skin flora to the essential oil of Melaleuca alternifolia (tea tree oil). Am J Infect Control. 1996Jun;24(3):186-9.
9. Carson CF et al. Antimicrobial activity of the major components of the essential oil of Melaleuca alternifolia. J Appl Bacteriol 1995 Mar;78(3):264-9.
10. Carson CF, et al. Susceptibility of methicillin-resistant Staphylococcus aureus to the essential oil of Melaleuca alternifolia. J Antimicrob Chemother. Mar1995;35(3):421-4.
11. Caelli M, Porteous J, Carson CF, et al. Tea Tree Oil as an Alternative Topical Decolonization Agent for Methicillin-resistant Staphylococcus aureus. J Hosp Infect. Nov2000;46(3):236-7.
12. Dryden MS, Dailly S, Crouch M. A randomized, controlled trial of tea tree topical preparations versus a standard topical regimen for the clearance of MRSA colonization. J Hosp Infect. Apr2004;56(4):283-6.
13. Carson CF et al. Mechanism of action of Melaleuca alternifolia (tea tree) oil on Staphylococcus aureus determined by time-kill, lysis, leakage, and salt tolerance assays and electron microscopy. Antimicrob Agents Chemother. 2002 Jun;46(6):1914-20.
14. Carson CF et al. Broth micro-dilution method for determining the susceptibility of Escherichia coli and Staphyulococcus aureus to the essential oil of Melaleuca alternifolia (tea tree oil). Microbios 1995;82(332):181-5.
15. Messager S et al. Assessment of the antibacterial activity of tea tree oil using the European EN 1276 and EN 12054 standard suspension tests. J Hosp Infect. 2005 Feb;59(2):113-25.
16. Hammer KA et al. In vitro susceptibilities of lactobacilli and organisms associated with bacterial vaginosis to Melaleuca alternifolia (tea tree) oil. Antimicrob Agents Chemother. 1999 Jan;43(1):196.
17. Hammer KA. Antifungal activity of the components of Melaleuca alternifolia (tea tree) oil. J Appl Microbiol. 2003;95(4):853-60.
18. Hammer KA et al. Antifungal effects of Melaleuca alternifolia (tea tree) oil and its components on Candida albicans, Candida glabrata and Saccharomyces cerevisiae. J Antimicrob Chemother. 2004 Jun;53(6):1081-5. Epub 2004 May 12.
19. Hammer KA et la. In vitro activity of Melaleuca alternifolia (tea tree) oil against dermatophytes and other filamentous fungi. J Antimicrob Chemother. 2002 Aug;50(2):195-9.
20. Nenoff P, et al. Antifungal activity of the essential oil of Melaleuca alternifolia (tea tree oil) against pathogenic fungi in vitro. Skin Pharmacol. 1996;9(6):388-94.
21. Concha JM, Moore LS, Holloway WJ. 1998 William J. Stickel Bronze Award. Antifungal Activity of Melaleuca alternifolia (Tea-tree) Oil Against Various Pathogenic Organisms. J Am Podiatr Med Assoc. Oct1998;88(10):489-92.
22. Tong MM, et al. Tea tree oil in the treatment of tinea pedis. Australas J Dermatol. 1992;33(3):145-9.
23. Buck DS, et al. Comparison of two topical preparations for the treatment of onychomycosis: Melaleuca alternifolia (tea tree) oil and clotrimazole. J Fam Pract. Jun1994;38(6):601-5.
24. Hammer KA et al. Susceptibility of oral bacteria to Melaleuca alternifolia (tea tree) oil in vitro. Oral Microbiol Immunol. 2003 Dec;18(6):389-92.
25. Jandera V, Hudson DA, de Wet PM, et al. Cooling the Burn Wound: Evaluation of Different Modalites. Burns. May2000;26(3):265-70.