The purpose of this study was to determine the effectiveness of Lactobacillus-containing vaginal tablets in the treatment of bacterial vaginosis (BV) and in the restoration of a healthy vaginal flora. Thirty-nine women with BV were enrolled in a double-blind, placebo-controlled clinical trial. Patients received either one Lactobacillus-containing tablet or placebo daily for 7 days. Clinical criteria, vaginal Gram stain scores and symptoms were compared with those at the initial visit and those at completion of therapy and 2 weeks later. After completion of therapy, all of the patients in the Lactobacillus-treated group (n = 18) were free of BV, showing a normal (83%) or intermediate (17%) vaginal flora, as compared with only two patients free of BV with intermediate flora (12%) from among the 16 placebo-treated women (p <0.001). Two weeks after completion of therapy, treatment was successful (score <7) in 61% of Lactobacillus-treated patients as compared with 19% of those in the placebo group (p <0.05). In the treatment group, the total number of symptomatic patients and the intensity of their symptoms, in particular vaginal malodour, were significantly reduced at both follow-up visits. The data indicate that intravaginal administration of exogenous selected strains of lactobacilli can restore a normal vaginal microbiota and be used in treating bacterial vaginosis.