Acne sufferers (338) were treated with minocin 50 mg bd [2x a day] (254 for 12 wk). A highly significant improvement trend (P < 0.0001) was found following analysis of visual analogue scales measuring severity of acne, area covered by acne, number of inflamed lesions, density of acne lesions. Over all, 79% of patients thought the therapy to be effective or very effective; 70% of patients continued on the same therapy after the study period. Mean 1st improvement was noted by the patient after 4 wk of treatment. Patients (122) had taken prior to oxytetracycline therapy, of these, 94 (77%) stopped oxytetracycline therapy because of lack of efficacy. After treatment of these oxytetracycline failures with minocin, a highly significant improvement trend (P < 0.0001) of acne was again seen. In this group, 75% of patients thought the minocin therapy to be effective or very effective; 69% continued minocin therapy after the study period. In all, 74% of patients having received prior oxytetracycline thought that minocin therapy was better than their previous therapy. Patients (93) had received either no previous therapy or topical therapy alone. Once again minocin treatment resulted in a highly significant improvement trend (P < 0.0001) in the severity of acne. Seventy-six (82%) of these patients thought that minocin therapy was effective or very effective. A total of 73% of patients continued with minocin therapy following the study period. Adverse events were noted in 6% of patients. Of these, 3% were definitely drug-related and only 6 (2%) of patients left the trial because of adverse reactions. None of adverse reactions reported were serious in nature. Minocin therapy was highly effective treatment for acne resulting in a rapid onset of action and good patient tolerance. Marked efficacy was seen even in those patients who had previously failed on oxytetracycline treatment.