Henna has been used since antiquity to dye skin, hair and fingernails, as well as fabrics including silk, wool and leather. Henna contains a compound called Lawsone. Lawsone (2-hydroxy-1,4-naphthoquinone), also known as hennotannic acid, is a red-orange dye present in the leaves of the henna plant (Lawsonia inermis) as well as in the flower of water hyacinth (Eichhornia crassipes).