100% Natural 2018 Crop Indigo powder. Indigo is a natural dye used to color your hair naturally, Indigo is 100% safe because it is derived from plant. Most black hair dyes contain PPD, a dangerous chemical that can cause allergic reactions but Indigo has no side effects and allergic reactions. Sometimes indigo is called "black Henna". Indigo is a natural plant. Our indigo is finely sifted AND is also fresh.