Dithranol (INN) or anthralin (USAN and former BAN) is a Hydroxyanthrone, anthracene derivative, medicine applied to the skin of people with psoriasis. It is available as creams, ointment or pastes in 0.1 to 2% strengths. The terms dithranol and anthralin are sometimes used synonymously. Anthralin cream is a topical antimitotic. It works by slowing the reproduction of skin cells, precise mechanism of anti-psoriatic action is not yet fully understood. However, numerous studies have demonstrated anti-proliferative and anti-inflammatory effects of anthralin on psoriatic and normal skin. The anti-proliferative effects of anthralin appear to result from both an inhibition of DNA synthesis as well as from its strong reducing properties. Recently, anthralin’s effectiveness as an anti-psoriatic agent has also been in part attributed to its abilities to induce lipid peroxidation and reduce levels of endothelial adhesion molecules which are markedly elevated in psoriatic patients. Unlike retinoids and PUVA, anthralin does not inhibit liver microsomal enzyme activity; consequently, the likelihood of adverse drug interactions is greatly reduced when other agents are administered concomitantly with anthralin.