Henna is a reddish dye prepared from the dried and powdered leaves of the henna tree.  It has been used since at least the ancient Egyptian period as a hair and body dye, notably in the temporary body art of mehndi (or "henna tattoo") resulting from the staining of the skin using dyes from the henna plant.

After henna stains reach their peak colour, they hold for a few days, then gradually wear off by way of exfoliation, typically within one to three weeks. Henna has been used in ancient Egypt, ancient Near East and then the Indian subcontinent to dye skin, hair and fingernails, as well as fabrics including silk, wool, and leather.

Historically, henna was used in West Asia including the Arabian Peninsula and in Carthage, other parts of North Africa, West Africa, Central Africa, the Horn of Africa and the Indian subcontinent. The name henna is used in other skin and hair dyes, such as black henna and neutral henna, neither of which is derived from the henna plant.