Tea Tree Oil Tea Tree Oil is inexpensive and safe when used as directed. What is tea tree oil and how does it work? Tea tree oil comes from the leaves of Melaleuca alternifolia, a small tree native to Queensland and New South Wales, Australia. Although Melaleuca alternifolia is known as the tea tree, it should not be confused with the plant whose leaves are used to make black, green, and oolong tea. Tea tree oil has been used as a