Henna comes from the leaves of the henna plant, scientifically known as Lawsonia inermis. The henna plant is a small tree that is native to the semiarid and tropical areas of northern Africa, Asia and Australia. Henna leaves contain an orange-reddish dye known as lawsone.
Henna is commonly used for temporary body decorations because lawsone binds to keratin in the skin, leaving orange or brown stains. Henna paste is made by crushing dried henna leaves into a powder, mixing the powder with a mildly acidic liquid, such as lemon juice or vinegar, and then allowing the paste to sit for up to 24 hours to allow the dye to be released from the leaf matter.