These chemicals are often undisclosed on packaging, and have a wide range of colors including what appears to be a natural looking color stain produced by dyes such as Sodium Picramate.Le henné, art des femmes de Mauritanie.

Henna only stains the skin one color, a variation of reddish brown, at full maturity 3 days after application.Physicians have urged governments to legislate against black henna because of the frequency and severity of injuries, especially to children.

page needed Doumas, Christos (1992).The high profit margins of black henna and the demand for body art that emulates "tribal tattoos" further encourage artists to deny the dangers.