Tea tree oil has been used for centuries to treat skin infections
Tea tree oil is derived from an Australian native tree the Melaleuca alternifolia, a member of the myrtle family. Tea tree oil is commonly used for skin and nail bacterial, fungal or viral infections. Tea tree oil contains 100 bio-active components. Terpinen-4-ol in tea tree oil causes antimicrobial activity and suppresses an inflammatory mediator. However, tea tree oil should be used with care as a number of problems have been reported.
Allergy
Tea tree oil is found in a number of commercial products, but tea tree oil can cause an allergic reaction in some patients. An Australian study published in 2007 in The Australasian Journal of Dermatology showed that 1.8 percent of patients had a positive patch test to oxidized tea tree oil, with 20 percent previously having used neat tea tree oil prior to the reaction. It is thought that the allergic reaction may be due to either contaminants or oxidation products.
Antibiotic Resistance
Tea tree oil is known to have a broad antimicrobial activity. This antimicrobial activity also includes bacteria such as MRSA and E.coli. A study by Ann McMahon and colleagues in 2007 and published in Journal of Antimicrobial Chemotherapy showed that though tea tree oil is an effective antimicrobial agent, inappropriate low concentrations of tea tree oil may contribute to antibiotic resistance in human pathogens.
Toxicity
Tea tree oil is toxic if swallowed, both for humans and pets. Case studies have shown that if tea tree oil if swallowed it can lead to neurological problems, vomiting, drowsiness and possibly coma. Data has shown that tea tree oil can be toxic in cats and dogs, particularly if the product is used incorrectly. Cats appear to be able to absorb tea tree oil through their skin causing toxicity, though they may absorb the oil while grooming. There is no known antidote to tea tree oil with the only treatment being supportive care.
Pregnancy and Hormones
The National Institute of Health indicates that there is no evidence that tea tree oil is safe either during pregnancy or childbirth. Tea tree oil may interfere with the strength of contractions and should therefore be avoided during child birth. A study published in The New England Journal of Medicine in 2007 described three cases where young boys had developed breasts, or gynecomastia, after using commercially available products containing lavender oil with tea tree oil. The study found that both lavender oil and tea tree oil altered the boys' sex hormones levels.
