Acitretin, a metabolite of etretinate, was given to 38 patients for the treatment of psoriasis. During the first 8 weeks patients received either placebo, 10 mg, 25 mg, 50 mg, or 75 mg of acitretin daily in a double-blind manner. The dosages of 10 mg and 25 mg daily did not achieve any statistically significant improvement in psoriasis over placebo; however, both the 50 and 75 mg dosages were statistically significantly better than placebo. Side effects were primarily mucocutaneous and occurred in most patients receiving 25 mg or more of acitretin daily. After the double-blind period, patients continued treatment in an open fashion until they had received a total of 24 weeks of acitretin therapy. Most patients received 50 mg of acitretin daily, which adequately cleared their psoriasis. After approximately 3 months without acitretin, most patients required retreatment. Subsequent 24-week courses of therapy were generally effective and well tolerated. The most common laboratory abnormalities were elevations of triglyceride, cholesterol, and liver transaminase levels. The efficacy and side effects of acitretin appear to be similar to those of etretinate; the principal advantage of acitretin is its shorter half-life. Although acitretin is a potent teratogen, its rapid elimination makes it a viable treatment for psoriasis among women of childbearing potential.