The essential oil of the tea tree is renowned for its antifungal and antiseptic qualities, and has enjoyed worldwide popularity since the 1980s. But, the people of its homeland have appreciated the health-giving benefits of tea tree for many centuries.

Tea tree was an important medicinal for Native Australians. They drank tea made of the leaves and applied tea tree poultices to treat wounds, cuts, and various skin disorders. There is a legend that tells of a lagoon reputedly endowed with magical powers, and the local natives would bathe in its waters to cure burns and wounds. This lagoon, as it turned out, had several tea trees growing near its banks and, presumably, falling leaves released their oils into the water, transforming the pool into an antiseptic bath.

During World War II, tea tree oil was added to machine "cutting" oils used in Australian munition factories to reduce the frequency of infections occurring from workers cutting their hands on sharp metal filings. Tea tree oil was so widely accepted as an effective germicide that it was standard issue in Australian Army and Naval first-aid kits.

Australian scientists had already begun clinical testing of the antibacterial properties of tea tree as early as the 1920s. One physician, Dr. Arthur Penfold of the Sydney Museum of Applied Arts and Sciences, found that tea tree oil was at least 10 times more effective than carbolic acid (phenol), the standard antiseptic in use at the time. Penfold presented tea tree oil as a "dependable and effective topical treatment" to the Royal Society in 1923. Soon, private physicians and public hospitals began using the oil to sterilize instruments, and to prevent infection, in patients who underwent surgery.

Pure tea tree oil contains 48 distinct known compounds, two of which are of critical importance -- terpinene-4-ol and cineole. Terpinene-4-ol is believed to be responsible for the healing potential of the oil, while cineole lends its antiseptic qualities. However, since all 48 compounds behave synergistically, variations in processing methods, and even differences occurring naturally in crops from year to year, can affect the quality .and efficacy of the oil. For instance, an elevated level of cineole can produce skin irritation and degrade the effects of terpinene-4-ol. For this reason, the Australian Standards Association (ASIA) has established certain criteria to ensure quality in manufacturing tea tree oil. According to ASA, quality tea tree oil must contain all 48 constituents, unadulterated; the terpinene-4-ol content must be no less than 30 percent of the entire solution, and the cineole content cannot exceed 15 percent. Typically, most tea tree oils found on the market contain from 35 percent to 45 percent terpinene-4-ol and 5 percent to 10 percent cineole.

There have been several recent studies that validate claims that tea tree oil is effective in inhibiting a wide range of organisms. In fact, the antifungal activity of tea tree oil has been assessed against at least 26 Strains of dermatophyte species of bacteria and 54 yeasts, 32 of which were strains of Candida spp. The oil was found to, be effective against all of them. In one study, conducted last year, by the Department of Podiatric Medicine and Surgery at Wilmington Hospital, Delaware, the activity of tea tree oil was evaluated against 58 clinical pathogens, including Candida, Aspergillus Trichophyton, Penicillium, and Epidermophyton species. Tea tree oil proved effective against all of the pathogens but a single strain of Escherichia floccosum. Tea tree oil has also has shown to be effective against Escherichia coli, in the test tube, and, in a gaseous state (vapor), it demonstrated the ability to suppress a number of airborne fungi. These studies offer evidence that tea tree oil is useful in treating vaginal yeast infections and respiratory infections, as well as a variety of skin disorders.

Tea tree oil is also reputed to speed healing and to have a mild analgesic effect, thereby reducing pain and inflammation. For this reason, the oil is often found in burn ointments and sunburn lotions. Research also indicates that tea tree oil kills germs that cause acne, warts, and boils and it inhibits infections associated with first and second-degree burns, while preventing scarring.

While tea tree oil is marveled as an "on-the-spot medicine in a bottle," its unique composition yields other long, lasting benefits, as well. Its complex chemical structure makes it difficult for bacteria to readily develop resistance to its therapeutic components. In a recent study published in the Journal of Hospital Infection, researchers found that a 0.5 percent solution of tea tree oil destroyed 60 strains of antibiotic-resistant Staphylococcus aureus, one of the "super germs" that can result in secondary infections in hospital patients. In addition, tea tree oil not only destroys germs on contact, but, because it is readily absorbed, it continues to block bacterial growth, at the site, for several days after the initial application. Standard antibiotics and antiseptics often inadequately perform both of these tasks.

In Australia, it's nearly impossible to find a medicine cabinet, or first-aid kit, devoid of tea tree oil. But the oil is also at home in much of Europe and in the United States. Among ingredients used in natural health and beauty products, tea tree oil is found in abundance. The oil is used in oral-hygiene products, skin lotions, shampoos (especially those formulated to treat dandruff, scalp infections, and to remove head lice), lip and mouth salves, and products designed to treat fungal infections of the nails.

Because of its disinfecting capability, tea tree is also a common ingredient in non-toxic household cleaners and is used in natural pet products geared to eliminate fleas and ticks.

REFERENCES

Chan, C.H., et al. "Activity of tea tree oil on methicillin-resistant Staphylococcus aureus," Journal of Hospital Infection 39(3):244-245, 1998.

Concha, J.M., et al. "Antifungal activity of Melaleuca alternifolia (tea tree) oil against various pathogenic organisms," Journal of the American Podiatric Medical Association 88(10):489-492, 1998.

Gustafson, J.E., et al. "Effects of tea tree oil on Escherichia coli," Letters In Applied Microbiology 26(3):194-198, 1998.

Hammer, K.A., et al. "In vitro activity of essential oils, in particular Melaleuca alternifolia (tea tree) oil and tea tree oil products against Candida spp.," Journal of Antimicrobial Chemotherapy 42(5):591-595, 1998.

Inouye, S, et al. "Antisporulating and respiration-inhibitory effects of essential oils on filamentous fungi," Mycoses 41(9-10):403-410, 1998

Nenoff, P, et al. "Antifungal activity of the essential oil of Melaleuca alternifolia (tea tree oil) against pathogenic fungi in vitro," Skin Pharmacology 9(6):388-394, 1996.

Veal, L. "The potential effectiveness of essential oils as treatment for headlice, Pediculus humanus capitis." Complementary Therapies in Nursing and Midwifery 2(4):97-101, 1996.