A version of Mehndi, an art that originated in India, henna tattoos are made from a dye derived from the henna shrub, which is native to southern Asia and northern Africa. The designs are drawn on the skin with a paste made of henna and left on for up to 12 hours. After they are removed, an orange stain remains, which darkens to red over 48 hours.
Henna tattoos last anywhere from three to 21 days, depending primarily on the thickness of the skin on which they are applied. Application of the designs may take anywhere from a few minutes to several hours, depending on the complexity of the design. Henna tattoos do not hurt and are completely safe; however, black henna (which is not traditional henna) includes the chemical p-phenylenediamine, which can cause liver damage and severe skin reactions.
In the art of Mehndi, henna designs are applied to the hands and feet of brides to decorate them for their weddings. Modern henna designs can be applied to any part of the body. Although people use the word "tattoo" to refer to henna, all it has in common with actual tattoos is its use for body ornamentation; unlike a tattoo, henna is not permanent.