Definition of Henna

Henna: A coloring made from the leaves of the Egyptian privet, Lawsonia inermis. Approved only for use as a hair dye, not for direct application to the skin, as in the body-decorating process known as mehndi. This unapproved use of a color additive to henna makes these products adulterated and therefore illegal. Injuries to the skin can result from products marketed as henna.