The efficacy of cyclosporin A (CyA) treatment was studied in seven patients with chronic dermatitis of the hands. CyA was started at a daily dose of 2.5 mg/kg in five patients, and 1.25 mg/kg in two patients. In patients who responded to the treatment at 2.5 mg/kg/day, the daily CyA dose was reduced stepwise, to the lowest maintenance dose of 1.25 mg/kg. In patients who did not respond, the dose was increased, to a maximum of 5 mg/kg/day. The patients were treated for 2-16 weeks. In six of the seven patients the dermatitis responded to CyA treatment within a few weeks. No response was seen with a starting dose of 1.25 mg/kg/day. In three of the five patients with a starting dose of 2.5 mg/kg/day, the daily CyA dose could be reduced to 1.25-2 mg/kg/day. After stopping CyA treatment, the dermatitis recurred during follow-up in three patients, three remained in remission, and one patient was not available for study. Treatment-related side-effects occurred in three patients. CyA treatment had to be stopped in one patient due to headache. The present study suggests that CyA could be a useful treatment for chronic dermatitis of the hands not responding to conventional therapy.