Anthralin was first synthesized in 1916. Earlier, a natural product, chrysarobin, originally derived from the South American araroba tree, had been used to treat psoriasis. Anthralin was first used in Germany, and later in the Ingram regimen in Britain, but it has never been popular with American dermatologists. This is probably due to the side effects of staining and irritation of the skin. Attempts to reduce these using low concentration, short contact therapy, and concomitant steroid therapy, have been only partially successful. It may be that better instruction of patients and physicians will lead to wider use of this effective topical agent for the treatment of psoriasis. The mode of action of anthralin is thought to be either through its effect on deoxyribonucleic acid (DNA), probably mitochondrial DNA, which reduces cell turnover, or through its effects on various enzyme systems, including those of polyamine synthesis and respiration. The aims of this review are to discuss historical aspects of anthralin and to update its chemistry, pharmacology, and clinical usage.