Background: The biologically active form of vitamin D₃, calcitriol, may offer a new therapeutic approach to psoriasis, Calcipotriol, a new vitamin D₃ analogue, is at least 100 times less calcemic than calcitriol.

Objective: Our purpose was to study the efficacy and safety of calcipotriol in the treatment of psoriasis vulgaris.

Methods: In a right/left comparative, double-blind study, treatment with calcipotriol ointment (50 μg/gm) twice daily and placebo was given for 4 weeks. The preferred treatment was continued, without opening the code, for another 4 weeks. Efficacy, as measured by the Psoriasis Area and Severity Index and by the investigator's and patient's global assessment, and safety were assessed every 2 weeks.

Results: The mean Psoriasis Area and Severity Index fell in 4 weeks from 14.2 to 6.3 with calcipotriol and from 14.1 to 9.2 with placebo (p < 0,001; 95% confidence interval for difference: 1.78→ 3.94). Local side effects were equally common with calcipotriol and placebo. The mean serum calcium remained unchanged.

Conclusion: Topical application of up to 50 gm of calcipotriol ointment per week was found to be an effective and safe treatment of psoriasis vulgaris.