Seventy-five patients, aged between 18 and 55, with clinical bacterial vaginosis were assigned to two treatments in a randomized fashion. One group received a single oral dose of 2 g tinidazole, the other 2 x 1 vaginal tablet of metronidazole 400 mg on five consecutive days. The clinical success rate (healing and improvement) was 97% in the group treated with tinidazole, and 84% in the group treated with metronidazole. One patient of the tinidazole group and six patients of the metronidazole group had to be given further treatment because of an inadequate response to therapy. Although there were no statistically significant differences between the two groups with respect to clinical effect and tolerance, the results do show that, for the treatment of bacterial vaginosis, a single dose of tinidazole represents a clinically effective and well-tolerated therapy that is minimally stressful for the patient and is particularly suitable for prescription by the practicing physician.