Topical vitamin D3is now widely accepted as a convenient and well-tolerated treatment modality for psoriasis. Among various biosynthetic vitamin D3analogues, 1,24-dihydroxycholecalciferol (tacalcitol), which is commercially available in Japan as an ointment containing 2μg/g, is unique because it does not induce any side-effects even when it is applied to facial psoriatic lesions. The clinical and histopathological similarities of seborrhoeic dermatitis to psoriasis led us to study the effectiveness of tacalcitol ointment for the treatment of the facial lesions of severe seborrhoeic dermatitis. We treated 15 patients with facial seborrhoeic dermatitis with topical applications of tacalcitol ointment twice daily. The lesions in 11 of the 15 patients markedly improved during the first 2 weeks of treatment. Only one patient stopped the treatment because of an enhancement of erythema and scaling during the first 2 weeks. In the final evaluation made after 6 weeks, two of the remaining three patients also showed marked improvement, and the other showed only slight improvement. Moderate improvement or better after 2, 4 and 6 weeks of treatment occurred in 73%, 83% and 89% of patients, respectively. There were no severe cutaneous or systemic adverse effects during the 6-week treatment period. None of the patients, who showed excellent responses, had relapsed at least 4 weeks after stopping treatment. We recommend this agent for severe facial lesions of seborrhoeic dermatitis.