Cranberry

People most often take cranberries to help prevent and relieve the symptoms of urinary tract infections (UTIs). The effectiveness of cranberries in preventing UTIs has not been confirmed. Natural unprocessed cranberry juice contains anthocyanidins (eg, proanthocyanidin), which prevent (UTIs). The effectiveness of cranberries in preventing UTIs has not been confirmed. Natural unprocessed cranberry juice contains anthocyanidins (eg, proanthocyanidin), which preventEscherichia coli from attaching to the urinary tract wall.

Some people take cranberry juice to reduce fever and treat certain cancers; however, there is no scientific proof that it is effective for these uses.Some people take cranberry juice to reduce fever and treat certain cancers; however, there is no scientific proof that it is effective for these uses.

In 2020, the U.S. Food and Drug Administration (FDA) authorized (allowed) qualified health claims for a reduced risk of recurrent UTIs in healthy women while also acknowledging there is limited and inconsistent credible scientific evidence to support these claims (1, 2).

In 1966, the first clinical trial, uncontrolled, evaluating the positive effects of cranberry juice in preventing UTIs was published (3). Since then, numerous trials have been performed evaluating different populations, severity of medical conditions, dosages, time, and form of supplement in juice or extract capsule/tablet.

The majority of evidence suggests that cranberry juice or extract can have a small, yet statistically significant effect on preventing the recurrence of UTIs over 12 months, but that supplementation cannot treat UTIs (4). However, a 2012 Cochrane review of 24 studies (4473 participants) placed some doubt on the effectiveness of the supplement, indicating a small trend toward fewer UTIs with supplementation; however, that finding was not statistically significant (5). A 2017 meta-analysis of 28 studies (4947 participants) found that UTIs are decreased significantly by 33% (6). A different meta-analysis of randomized controlled trials in women at risk for UTIs also found that cranberry reduced UTI risk by 26% (7).

A 2023 Cochrane review of 50 studies in 8857 patients reported that cranberry products may reduce the risk of symptomatic, culture-verified UTIs by 30% (A 2023 Cochrane review of 50 studies in 8857 patients reported that cranberry products may reduce the risk of symptomatic, culture-verified UTIs by 30% (8). In women with recurrent UTIs the risk reduction was 26%; in children with UTIs, the risk was reduced by 54%; and in people prone to UTIs risk was reduced by 53%. However, relative risk reduction was not supported in pregnant women, older adults, or people with neuromuscular bladder dysfunction or bladder-emptying problems.

Standardization of cranberry products and specifying proanthocyanidin (PAC) content may help to clarify results and resolve the discrepancy. Physiologic differences in the urinary tract and proper hygiene of female individuals studied also could contribute to the variability in response. Due to concern for antibiotic resistance, the American Urological Association 2019 guidelines in women with recurrent UTIs stated that clinicians may offer cranberry prophylaxis, although this is a Grade C evidence level recommendation (9).

No adverse effects are known. However, because most cranberry juice is highly sweetened to offset its tart taste, people with diabetes should not consume cranberry juice unless it is artificially sweetened. Because cranberry increases urinary acidity, it may promote stone formation in patients with uric acid kidney stones.

Cranberry products may increase the effects of warfarin. products may increase the effects of warfarin.Cranberry may increase the effect of the statin atorvastatin and the antihypertensive nifedipine.may increase the effect of the statin atorvastatin and the antihypertensive nifedipine.

1. 1. FDA Announces Qualified Health Claim for Certain Cranberry Products and Urinary Tract Infections. Accessed February 27, 2025.

2. 2. Health Claim Petition - Consumption of Cranberry Products and Reduced Risk of Recurrent Urinary Tract Infection in Healthy Women (Docket No. FDA-2018-Q-0739). Accessed February 27, 2025.

3. 3. Papas PN, Brusch CA, Ceresia GC. Cranberry juice in the treatment of urinary tract infections. Southwest Med. 47(1):17-20, 1966.

4. 4. Jepson RG, Craig JC. A systematic review of the evidence for cranberries and blueberries in urinary tract infection prevention. Mol Nutr Food Res. 51(6): 738-745, 2007. doi: 10.1002/mnfr.200600275

5. 5. Jepson RG, Williams G, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 10:CD001321, 2012. doi: 10.1002/14651858.CD001321.pub5

6. 6. Luís Â, Domingues F, Pereira L. Can cranberries contribute to reduce the incidence of urinary tract infections? A systematic review with meta-analysis and trial sequential analysis of clinical trials. J Urol. 198(3):614-621, 2017. doi: 10.1016/j.juro.2017.03.078

7. 7. Fu Z, Liska D, Talan D, et al. Cranberry reduces the risk of urinary tract infection recurrence in otherwise healthy women: a systematic review and meta-analysis. J Nutr. 147(12):2282-2288, 2017. doi: 10.3945/jn.117.254961

8. 8. Williams G, Stothart CI, Hahn D, Stephens JH, Craig JC, Hodson EM. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2023 Nov 10;11(11):CD001321. doi: 10.1002/14651858.CD001321.pub7

9. 9. Anger J, Lee U, Ackerman AL, et al. Recurrent uncomplicated urinary tract infections in women; AUA/CUA/SUFU guideline. J Urol. 202(2):282-289, 2019. doi: 10.1097/JU.0000000000000296

The following English-language resource may be useful. Please note that The Manual is not responsible for the content of this resource.

1. National Institutes of Health (NIH), National Center for Complementary and Integrative Health: Cranberry