Tea tree oil is an essential oil distilled from the Australian plant Melaleuca alternifolia. It has been used medicinally by Australian Aborigines for centuries and was identified as an antiseptic by the New South Wales chief chemist in the 1920s. In the decades since, tea tree oil has also been found to have substantial anti-fungal, antibacterial, anti-viral and anti-inflammatory activity. The oil is steam-distilled and has been produced and marketed in Australia for the past 80 years. It is only in the past 20 years, however, that Melaleuca alternifolia has been cultivated intensively as a commercial agricultural crop. The species is unique to Australia and plants with the genetic makeup necessary to produce the oil are native to northern New South Wales. Consequently, it is here that most commercial production occurs. There is currently around 3000 hectares of cultivated tea tree growing in Australia and about 100 producers. More than 80 per cent of the world’s tea tree oil is produced in Australia. Almost 90 per cent of Australian tea tree oil is exported, principally to North America and Europe.
The oil of Melaleuca alternifolia has more than 100 components. The most abundant of these is terpinen- 4-ol which makes up at least 30 per cent and has an important role in the oil’s antimicrobial activity. Fungi are significant human pathogens, causing common superficial infections. A study conducted in 2002 found that tea tree oil can inhibit and kill yeasts, dermatophytes (which cause superficial nail and skin infections) and other filamentous fungi. The sorts of infections or conditions that are associated with fungi and which may be suitable for treatment with topical tea tree oil included dandruff and seborrhoeic dermatitis (caused by Malassezia yeasts).