Cranberry products—particularly cranberry juice—are widely used as a nonpharmacologic approach to prevention and treatment of urinary tract infections (UTIs). However, it is not clear that—when systematically compared with placebo or other treatments—cranberry products actually prevent UTIs. In this JAMA Clinical Evidence Synopsis, Jepson and colleagues summarize the results of a systematic review and analysis of data from 24 clinical trials (4473 patients) that compared cranberry juice or cranberry products with placebo, no treatment, or another treatment on the incidence of UTIs. The authors found that cranberry products are not associated with prevention of UTIs. However, the lack of an association may be related to poor adherence to therapy, insufficient active ingredient in the cranberry product tested, or lack of statistical power in the studies analyzed.