One hundred symptomatic women with clinical bacterial vaginosis (BV) were enrolled in this study. The bacteriological epidemiology of BV and efficacy of oral or vaginal administration of antimicrobial agents for treatment of BV were investigated. The epidemiology of BV was investigated before antimicrobial therapy. Fifty patients were treated with oral administration of metronidazole (MTN), 500 mg twice a day, and 50 patients with 2% clindamycin (CLDM) phosphate in a vaginal cream, 5 g once a day for 7 days. The major organisms occurring were Streptococcus agalactiae, Escherichia coli, Gardnerella vaginalis, Peptostreptococcus species, Bacteroides species, Prevotella species, and Mobiluncus species and opportunistic pathogens such as Staphylococcus epidermidis and Enterococcus faecalis. The therapeutic efficacy of CLDM cream on BV appeared to be preferable to oral MTN from clinical and bacteriological aspects. The clinical and bacteriological effectiveness of MTN and CLDM in the treatment of BV suggests that anaerobes might play a major role in causing the clinical symptoms in patients with BV.