4-Amino-2-Hydroxytoluene is a substituted aromatic compound used in the formulation of permanent hair dyes, colors and tints. 4-Amino-2-Hydroxytoluene is used as a coupler in cosmetic hair dye formulations. The compound has a low oral toxicity in animals and has no significant mutagenic or teratogenic effects. The compound, at most, is a weak skin and eye irritant and, at most, a weak sensitizer. Carcinogenic skin painting studies of hair dyes containing this compound were negative. A variety of epidemio-logic studies have given no indication of a carcinogenic effect from the use of hair dyes.