Calcipotriol (calcipotriene) is a vitamin D-3 analogue which inhibits cell proliferation, enhances cell differentiation and appears to influence immunological factors which may play a role in the origins of psoriasis. In patients with chronic plaque psoriasis, twice-daily topical calcipotriol 50 mu g/g is more effective than unmedicated vehicle, betamethasone (betamethasone valerate), fluocinonide, dithranol (anthralin) and coal tar in patients with nonscalp psoriasis; however, patients with scalp psoriasis respond better to betamethasone than calcipotriol. In the treatment of patients with severe psoriasis, calcipotriol risen together with cyclosporin or psoralen ultraviolet A yields superior results to those achieved with either regimen alone. The efficacy of calcipotriol demonstrated in short term trials is sustained in noncomparative studies of up to 1 year in duration. Data from several clinical trials involving nearly 2000 patients show that calcipotriol is well tolerated the most common adverse events being mild and transient irritation of lesions or perilesional skin which occur in 15.1 to 25.8% of patients. At recommended dosages hypercalcaemia and hypercalciuria are very rare. Calcipotriol is better tolerated than short-contact dithranol, but causes more adverse events than betamethasone particularly in patients with scalp psoriasis. In conclusion, wide clinical trial experience has established calcipotriol as an effective and well tolerated topical therapy for the management of psoriasis. Calcipotriol can thus be considered to be an important option in the treatment of this difficult disorder.