Tea tree is a member of a genus of Australian and New Zealand trees and shrubs known as honey myrtles or bottlebrush trees. Many of the 100 or so species of tea tree have fragrant, essential oil-containing leaves. At least three species of bottlebrush trees are distilled for their essential oil: Melaleuca alternifolia, from which we get tea tree oil; Melaleuca cajeputi, which yields cajeput essential oil; and Melaleuca viridiflora, the source for niaoli essential oil. Distilled cajeput and niaoli oils retain some of the sweet-woody aromas present in the fresh leaves. Cajeput and niaoli oils are slightly less medicinal smelling than tea tree oil.
Although tea tree oil has a history of use as an herbal medicine, it wasn't until modern biochemists and aromatherapists defined the therapeutic nature of its essential oil that it became widely popular as an alternative medicine. Tea tree leaves have been used by Australian aboriginal people for treating cuts and wounds. The freshly crushed leaves are applied directly to an injury, then secured in place with a mud pack. Apparently the medicinal affects of this tea tree poultice are so powerful that they not only combat infection in the wound but overcome the potential for further infection caused by the application of the less than sterile mud pack.
Europeans learned of tea tree's effects as a folk medicine when they came to settle in Australia in the 19th century. Gradually the scientific community began to research and document the effects of the plant, especially the bactericidal and germicidal properties of the oil.
The key to tea tree's medicinal effectiveness is the ratio of two chemical constituents present in the oil: cineole and terpinen. Although both of these constituents are bactericidal and germicidal, cineole can be a powerful skin irritant. Therefore tea tree oils with low cineole and high terpinen contents are preferred.
The cineole/terpinen ratio can vary considerably in the many species of tea tree. The ratio can even vary in the same species growing in different areas. Plants which are identical other than their chemical make-ups are known as chemotypes. This variance prompted the creation of an Australian standard for a minimum terpinen content of 30% and a maximum cineole content of 15%. Now that the plant has been brought into cultivation, a process of selecting and propagating choice plants has produced tea tree oils that surpass the Australian standard, with terpinen contents as high as 40% and cineole contents as low as 5%. When the standard is exceeded in this way, the effectiveness of the oil remains high while its possible irritant effects decrease.
In aromatherapy, tea tree essential oil is employed for its physical, rather than emotional or aesthetic nature. This isn't to say that the strongly medicinal aroma of tea tree is offensive. Many appreciate its underlying intensely warm, nutmeg-like scent.
Some of the most effective aromatherapy uses for tea tree oil are cosmetic in nature. For instance, tea tree has a marked oil dissolving and dispersing action, which can help alleviate overly oily secretions of the skin. One way to take advantage of tea tree's natural astringent action is to dilute 12 drops of the oil in about three ounces of warm water and gently wipe freshly cleaned skin with the mixture using a soft cotton ball.
An oily scalp can also benefit from an application of tea tree. Before shampooing, a gentle massage with a few drops of the oil will gently invigorate the scalp and help lift greasy deposits from the hair shaft.
Because of the mild qualities of tea tree's terpinen content, the oil can soothe cuts, scratches, sunburn and cold sores. Because it's non-irritating, a single drop of the oil can be applied directly to minor injuries once or twice a day.
For a soothing sunburn treatment, tea tree is especially effective when paired with lavender oil. Add five drops of tea tree and 11 drops of lavender oil to three ounces of cool, distilled water. Place this mixture in a bottle with a spray atomizer attachment and mist sunburned areas whenever cooling relief is needed.
Other oils that sweeten tea tree's medicinal aroma include clary sage, geranium and marjoram. Spice oils like nutmeg and cinnamon increase the warm-woody notes of tea tree. This spicy blend is good for wintertime diffusion during the cold and flu season.
Tea tree oil is an important therapeutic and cosmetic essential oil. Despite its less than beautiful fragrance it should figure prominently in any beginner or advanced aromatherapist's repertoire.