Because of the many differences among studies of single-dose antimicrobial therapy for uncomplicated urinary tract infection in women, we reviewed the 14 randomized controlled trials on this subject. Twelve concluded that single-dose therapy was as effective as conventional multiple-dose therapy. Although the studies were carefully conducted, none both reported and ascertained in a blinded manner the incidence of adverse drug reactions. Also, no study included enough patients to prevent type II error. To circumvent the problem of having too few patients in each study, we used a rational strategy for pooling the data from the reviewed studies. Single-dose amoxicillin (3 g) was significantly less effective than conventional multidose therapy (69% vs 84%), while single-dose sulfamethoxazole-trimethoprim (two or three double-strength tablets) was indistinguishable from multidose, although there still were too few patients to exclude type II error. More research on this subject is needed with greater attention to sample size and blinded ascertainment of adverse reactions.