p-Phenylenediamine and its salts

PPD is an organic compound with the formula C₆H₄(NH₂)₂. In its pure form, paraphenylenediamine is a white crystal that oxidizes to a brown or dark brown.

Paraphenylenediamine is a dark pigmentation in hair dyes. Altering the paraphenylenediamine concentration with an oxidizing agent, such as hydrogen peroxide, can achieve a variety of shades. Shades can range from golden blonde in lower concentrations to jet black in higher concentrations.

A growing trend, particularly in underdeveloped and developing countries, is the consumption of paraphenylenediamine-containing products, such as black henna.