Eighty-one patients with rosacea were treated with either I% metronidazole cream or the cream base as a placebo for two months. The trial was performed double-blind, and the patients were assessed once each month. The variates studied were: (I) overall clinical assessment, (2) lesion counts, (3) degree of erythema, (4) independent photographic evaluation, and (5) patient's opinion. Four patients dropped out of the trial (one treated with metronidazole, three with placebo). In all the variates, I% metronidazole cream proved to be significantly more effective than placebo.