A water based 5% benzoyl peroxide gel (Benzac W5) was compared with topical 1% clindamycin phosphate solution (Cleocin T) in the treatment of acne vulgaris using a randomized, investigator blind study design. Lesion counts were significantly reduced in both treatment groups over the 12-week study period; however, the reduction of total lesions produced by benzoyl peroxide gel was significantly greater than that produced by clindamycin phosphate (P less than 0.05). Clindamycin phosphate had a milder effect on the skin surface in terms of peeling and drying than the benzoyl peroxide gel.