Changes in body weight and the incidence of estrogen-related side effects with low-dose oral contraceptives (OCs) containing 20 microg ethinyl estradiol (EE) have not been demonstrated in placebo-controlled trials. Two placebo-controlled, randomized trials demonstrated the efficacy of a low-dose OC for the treatment of acne in healthy females (n = 704; >or=14 years old) with regular menstrual cycles and moderate facial acne. Patients were randomized to receive 20 microg EE/100 microg levonorgestrel (LNG) or placebo for six cycles. Body weight was measured at baseline and during Cycles 1, 3, and 6. The occurrence of adverse events was recorded at each visit. Mean changes in weight from baseline were similar with 20 microg EE/100 microg LNG [0.72 kg +/- 2.64 (SD; n = 349)] and placebo [0.56 kg +/- 2.64 (SD; n = 355; p > 0.05)] for the last measured weight of each patient. Rates of headache, nausea, weight gain, and breast pain, side effects commonly attributed to OCs, were also similar between groups (p > 0.05). No serious, unexpected, drug-related adverse events occurred during the study. The low-dose OC containing 20 microg EE/100 microg LNG is safe, well tolerated, and does not cause weight gain.