To compare and assess ingestion of yogurt that contained live Lactobacillus acidophilus with pasteurized yogurt as prophylaxis for recurrent bacterial vaginosis (BV) and candidal vaginitis, we designed a crossover trial during which patients were examined monthly for candidal infection and BV while they were receiving either a pasteurized yogurt or a yogurt that contained live L acidophilus. Forty-six patients in 2 groups of 23 were randomly assigned to each of the study groups. At least 28 (61%) participated during the first 4 months of the study. Seven patients completed the entire study protocol. We concluded that daily ingestion of 150 mL of yogurt, enriched with live L acidophilus, was associated with an increased prevalence of colonization of the rectum and vagina by the bacteria, and this ingestion of yogurt may have reduced episodes of BV.