Tea tree oil is a yellow- or green-tinged essential oil with a fresh camphoraceous odour. It is extracted from the leaves of the tree Melaleuca alternifolia which is native to the northeast coast of New South Wales, Australia. The oil is claimed to have benefical cosmetic and medical properties (including antiseptic and antifungal action).
Preliminary scientific research (mainly in vitro) supports claims for various health benefits. Inhaled, tea tree oil is said to make breathing easier by "breaking up congestion". It supposedly can alleviate a sore throat and minimize the symptoms of cold, flu and systemic fungal infections. It seems effective against candidiasis and other vaginal infections and for hemorrhoids. As a bath additive it may control bacteria in spas and pools. It is used for fungal nail infections, athlete's foot, foul body odour, burning feet, etc. Massaging tea tree oil into the affected area may alleviate the discomfort of sore muscles or joint injuries. It also reduces hypertrophic scarring.
A patch test may be advisable before using items containing tea tree oil, since it can be allergenic and cause skin irritation or rash. Tea tree oil can also cause toxicity if ingested internally, and may result in dizziness, nausea and disorientation.