Summary Fifteen patients with Darier's disease (five patients), epidermolytic hyperkeratosis (five patients), and pityriasis rubra pilaris (five patients) were treated with doses ranging from 1.0 to 3.0 mg per kg body weight of 13 ‐cis retinoic acid. There was marked clinical improvement in the patients with Darier's disease which was sustained in two out of five on stopping treatment after 6 months. Three patients with pityriasis rubra pilaris went into remission, and required no further treatment on stopping 13‐cis retinoic acid after 6 months; however two patients did not respond at all. All five patients with epidermolytic hyperkeratosis responded, but relapsed rapidly on discontinuation of therapy. The major histological change noted was the reduction in stratum corneum organisation and cohesion, with reduction in stratum corneum layers. Serum cholesterol and triglycerides became raised after 1 month's therapy, but tended to fall during the following 5 months of therapy. High density lipoproteins remained depressed during treatment. In selected cases, 13‐cis retinoic acid is a useful therapy for Darier's disease, pityriasis rubra pilaris and epidermolytic hyperkeratosis.