Tea tree oil, also known as melaleuca oil or ti tree oil, is an essential oil with a fresh camphoraceous odor and a colour that ranges from pale yellow to nearly colourless and clear. It is derived from the leaves of the tea tree, Melaleuca alternifolia, native to Southeast Queensland and the Northeast coast of New South Wales, Australia.

Although there is little evidence of efficacy, as a folk medicine it is typically used as a topical medication in low concentrations for the attempted treatments of skin conditions. Tea tree oil is claimed as useful for treating dandruff, acne, lice, herpes, insect bites, scabies, and skin fungal or bacterial infections.