Pure cranberry juice, cranberry extract, or cranberry supplements may help prevent repeated UTIs in women, but the benefit is small. It helps about as much as taking antibiotics to prevent another UTI.footnote 1 Using cranberry products to prevent UTIs may be expensive, and some women complain of the taste. No single concentration of cranberry juice, extract, or supplement has been studied, so it's hard to know which product to choose.
If you do want to try cranberry juice to prevent UTIs, it's better to drink pure, unsweetened cranberry juice (rather than cranberry juice cocktail). Drinking cranberry juice cocktail doesn't seem to prevent UTIs better than drinking any other fruit juice.footnote 2
There is no proof that cranberry can cure a UTI. Cranberry is not well tested as a UTI treatment.
Medical Review:E. Gregory Thompson MD - Internal Medicine & Adam Husney MD - Family Medicine & Avery L. Seifert MD - Urology
Jepson RG, et al. (2012). Cranberries for preventing urinary tract infections. Cochrane Database of Systematic Reviews, (10).
Barbosa-Cesnik C, et al. (2011). Cranberry juice fails to prevent recurrent urinary tract infection: Results from a randomized placebo-controlled trial. Clinical Infectious Diseases, 52(1): 23-30.