In this prospective study, 51 patients suffering from psoriasis and ichthyosis were treated with acitretin for 2 years. The average dose was 0.5 mg/kg/day. We have evaluated the efficacy and side effects, focusing on skeletal side effects. X-ray examinations were done before treatment and after 1 and 2 years. Forty-five patients completed the study. Acitretin had a good clinical effect, with 75% improvement in 35 of the patients. Apart from the well-known side effects affecting the mucous membranes, one patient developed biopsy- proven toxic hepatitis. In 2 patients we observed unusual skeletal calcifications located in the forearms and in the hip. These were considered to be caused by the drug. In this study, which included patients up to 71 years, only radiographs of the pelvis and the forearms were of value as routine follow-up films.