Q. I’ve noticed that a lot of skin products and even toothpaste in health food stores contain tea tree oil. What is tea tree oil and why is it in all of these products?

A. Tea tree (Melaleuca alternifolia) is a small tree native to only one area of the world—the northeast coastal region of New South Wales, Australia. The leaves are the source of a valuable therapeutic oil—tea tree oil. Tea tree oil possesses significant antiseptic properties and is regarded by many as the ideal skin disinfectant, as it is active against a wide range of organisms, possesses good penetration, and is non-irritating to the skin. A variety of tea tree oil-based products exist in the marketplace, including toothpastes, shampoos and conditioners, creams, hand and body lotions, soaps, gels, liniments, and nail polish removers. Apply as instructed on the product label. Some people are allergic to tea tree oil, so use it cautiously the first time (apply it to only a small area of the skin).

Although there is a shortage of clinical studies, tea tree oil has been used as an antiseptic in the following conditions: acne, athlete’s foot, boils, burns, carbuncles, corns, impetigo, infections of the nail bed, insect bites, lice, mouth ulcers, psoriasis, ringworm, sinus infections, and vaginal infections.