Henna temporary tattoos are temporary body art designs drawn with a coloring made from an African and Asian flowering plant. The color of henna temporary tattoos is a reddish brown. However, some people blacken henna with a coal-tar hair dye that can be dangerous.
Henna temporary tattoos are applied to the surface of the skin, unlike permanent tattoos which are injected into the second layer of the skin. So-called "black henna" temporary tattoos sometimes produce adverse reactions including blisters, increased sensitivity to sunlight, loss of pigmentation, redness, weeping lesions and even permanent scarring, and these reactions may take two to three weeks to appear. The coal-tar hair dye sometimes used to blacken henna is illegal for use in cosmetics applied to the skin.