Coal tar: past, present and future.

Crude coal tar has been used in the treatment of dermatoses for many decades. In the last few years its use has been limited to skin diseases such as psoriasis and chronic dermatitis. Newer topical modalities for psoriasis are being used increasingly for treatment, but have failed to replace crude coal tar as a first-line treatment of psoriasis. We review the pharmacology, chemistry and use of crude coal in order to reappraise its role as a therapeutic agent in dermatology.