Topical vitamin D modulators are among the most widely used medications for the treatment of psoriasis. Calcitriol, the naturally occurring active form of vitamin D3, has long been used for topical psoriasis therapy in Europe and other parts of the world and was recently approved in the United States. Calcitriol 3 microg/g ointment has been extensively evaluated for the treatment of chronic plaque-type psoriasis and has been shown to be effective, safe and well-tolerated in a number of short-term and long-term clinical trials. Pharmacokinetic studies in patients with psoriasis and healthy control subjects have demonstrated that topical calcitriol ointment produces little systemic absorption of calcitriol and does not alter systemic calcium homeostasis significantly even when applied to approximately one third of the body surface area. Calcitriol ointment is associated with a low rate of cutaneous irritation and does not increase the sensitivity of treated skin to phototoxicity following treatment with ultraviolet treatment. In two randomized, double-blind clinical trials, twice-daily application of calcitriol ointment for eight weeks resulted in clearing or minimal residual psoriasis in approximately 34% of patients, compared with 12% to 22.5% of patients treated with vehicle ointment (P=0.005 in study 1 and P<0.001 in study 2). Calcitriol ointment also significantly improved ratings of individual psoriasis signs and symptoms of plaque elevation, erythema, scaling and pruritus compared to vehicle. In two long-term studies in which patients were treated with calcitriol ointment for a year or longer, calcitriol ointment produced sustained improvement in physician-rated and patient-rated psoriasis severity. Calcitriol ointment was associated with a low risk of adverse events after one year and did not alter laboratory measures of calcium or phosphorus metabolism in a clinically significant manner. The results of these studies suggest that calcitriol 3 microg/g ointment is an effective, safe and well-tolerated topical psoriasis therapy. Calcitriol ointment offers considerable flexibility for use in a variety of monotherapy and combination therapy regimens for patients with psoriasis.