Tea tree oil comes from the leaves of the tea tree (Melaleuca alternifolia). It grows in the swampy southeast Australian coast.

The tea tree was named by eighteenth century sailors, who made tea that smelled like nutmeg from the leaves of the tree. The chemicals in tea tree oil might kill bacteria, fungus, and mites, and reduce allergic skin reactions by decreasing swelling.

People use tea tree oil for acne, toenail fungus, and athlete's foot. It's also used for dandruff, lice, bad breath, and other conditions, but there is no good scientific evidence to support its other uses.

Do not confuse the tea tree with the unrelated common tea plant that is used to make black and green teas.