Tea tree oil is an essential oil distilled from the leaves of Melaleuca alternifolia, a plant native to Australia. It has been used in traditional medicine to treat colds, cough and skin infections.
The medicinal properties of tea tree oil were first reported in the 1920s. Its antiseptic effects were found to be several folds greater than phenol, a compound that was used extensively at the time to prevent infections. Following this discovery, tea tree oil was incorporated in many topical formulations to treat cutaneous infections and to accelerate wound healing. It is also found as an ingredient in skin and hair products.
In vitro studies indicate wide-spectrum antimicrobial (2) (12), antiviral (20), antiprotozoal (21), anti-inflammatory (22) and antiproliferative (14) (15) properties. Topical application of tea tree oil was shown to have cytotoxic effects in mice bearing subcutaneous tumors (23).
Clinical studies suggest its efficacy in treating acne (5), tinea pedis (6) (9), distal subungual onychomycosis (7), histamine-induced skin inflammation (8), dandruff (10), warts (16), cold sores (11), recurrent chalazion (26), and experimental contact dermatitis (18). A systematic review found that aromatherapy with tea tree oil led to reductions in anxiety and depression scores, improved sleep and resulted in an overall increase in well-being in cancer patients (24).