The activity and tolerance of 200 mg clotrimazole vaginal tablets and 150 mg econazole vaginal ovules were compared in the treatment of vaginal candidiasis in a controlled multicenter (3 centers) study. Treatment was allocated according to a randomized list and each investigator treated 20 patients per group. Duration of therapy was 3 days. Follow-up investigations were carried out approximately 1 and 4 weeks after commencement of treatment. The results were analyzed for 54 patients treated with clotrimazole and 57 with econazole; 9 patients were excluded from the analysis because of insufficient data. At the first follow-up examination, 1 week after starting therapy, 93.7% of patients on clotrimazole and 83.7% of patients on econazole had negative cultures. The success of therapy, as judged by the clinicians, was 95.8% for clotrimazole and 88.0% for econazole. For the first and fourth week combined reviews, 86.0% of clotrimazole patients and 77.8% of econazole patients had negative cultures and the success of therapy was 88.4% for clotrimazole and 80.0% for econazole. These differences were not statistically significant but there was a clear numerical superiority for clotrimazole. Tolerance was good in all the patients and no side-effects were observed. One can conclude that the treatment of vaginal candidiasis with a 200-mg vaginal tablet of clotrimazole over 3 days is highly effective and comparable with other established treatment regimes.