OBJECTIVE To compare the safety and efficacy of intravaginal clindamycin 2% cream with placebo in nonpregnant women with bacterial vaginosis. METHODS A randomized, double-blind, placebo-controlled clinical trial. METHODS Ambulatory patients in the general community. METHODS Two hundred fifteen nonpregnant outpatients with a diagnosis of bacterial vaginosis were entered into this study. Of the 134 evaluable patients, 65 received clindamycin and 69 placebo. Demographic parameters were comparable between the two treatment groups. METHODS Study subjects were equally randomized to receive either 5 g of clindamycin 2% vaginal cream or placebo cream for seven nights. METHODS Clinical and microbiologic follow-up evaluations were scheduled for 5-10 days and 25-39 days posttreatment. Patients were interviewed about signs and symptoms, adverse events, and compliance. Diagnostic examinations were performed. RESULTS Clinical success rates (cure and improvement) occurred in 50 of 65 patients who received clindamycin (77 percent) and 17 of 69 patients who received placebo (25 percent) by the first posttreatment visit (p < 0.001). Microbiologic cures or improvement were observed in 59 of the 65 patients treated with clindamycin (91 percent) compared with 20 of 69 placebo-treated patients (29 percent) (p < 0.001). At the end of the study, clinical and microbiologic cures or improvement were evident in 45 of 57 (79 percent) and 37 of 57 clindamycin-treated patients (65 percent), respectively, and 18 of 51 (35 percent) and 14 of 51 (28 percent) of the placebo-treated patients, respectively. The success rates with clindamycin 2% cream were statistically higher than those with placebo. The adverse-effect profiles in the two groups were similar and no serious adverse effects were reported. Patients who received clindamycin had a statistically higher incidence of nonbacterial vaginitis/cervicitis (18.5 vs. 7.5 percent, p = 0.003). CONCLUSIONS Intravaginal clindamycin 2% cream appears to be an effective and safe treatment of symptomatic bacterial vaginosis in nonpregnant women.