Changes in the indigenous vaginal microflora with uropathogenic bacteria can predispose women to frequently recurring bacterial cystitis. Lactobacilli used as probiotics have played an important role in preventing the colonization of pathogenic bacteria in the vagina. A prospective clinical pilot study was performed to confirm the safety and effectiveness of Lactobacillus vaginal suppositories against the recurrence of bacterial urinary tract infection (UTI). The patients enrolled in the study were instructed to administer vaginal suppositories containing the strain Lactobacillus crispatus GAI 98322. A significant reduction in the number of recurrences was noted, without any adverse complication (P=0.0007). The administration of vaginal suppositories containing L. crispatus GAI 98332 seemed to be a safe and promising treatment for the prevention of recurrent UTI.