Common Names

  • Mossberry
  • Sassamanash
  • Bounceberry

For Patients & Caregivers

How It Works

Cranberry juice or extracts have not been shown to treat or prevent cancer. It may be helpful for urinary tract infections (UTIs) in limited populations, but there is not enough evidence to recommend it for UTI prevention.

Cranberries contain compounds known as proanthocyanidins that have been shown to prevent bacteria from attaching to the bladder wall, which could cause UTIs. Human studies suggest it may be helpful for this purpose in some limited populations, including prostate cancer patients, but overall evidence is conflicting. Cranberry may also prevent bacteria from attaching to the stomach lining and areas in the mouth. Although lab studies suggest activity with several types of cancer cells, this has yet to be confirmed in human studies.

In patients who are prone to kidney stones, regular use of cranberry should be limited as it contains oxalates, a compound found in the most common form of kidney stones.

Purported Uses

  • Prevention and treatment of urinary tract infections (UTIs)
    The evidence for this claim is mixed.
  • Anticancer effects
    Lab studies show that cranberry juice extract and isolated compounds can inhibit various types of cancer cells, but this has not been confirmed by clinical trials.
  • Prevention of stomach ulcers
    Cranberry juice may help to prevent or suppress H. pylori infection.
  • Prevention of atherosclerosis
    Although one study in healthy volunteers does not suggest benefit, another study in diabetic men suggests cranberry juice may help to reduce heart disease risk factors.
  • Prevention of gum disease/cavities
    In the lab, cranberry juice prevents bacteria from attaching to one another thereby slowing down plaque formation.

Do Not Take If

  • You are taking warfarin: Because data is mixed on whether cranberry juice may increase bleeding, usage of cranberry juice should be monitored by a healthcare professional, if not avoided. Case reports of bleeding and death in 2 elderly patients who used cranberry juice and warfarin have occurred.

  • You are taking CYP450 substrate drugs: Cranberry may increase blood levels of these drugs or their adverse effects.

  • You are taking UGT substrate drugs: Cranberry may increase the risk of side effects for these drugs.

  • You have a history of kidney stones: Cranberry contains high concentrations of oxalate, a component common to kidney stones.

Side Effects

  • Nausea, vomiting and diarrhea have occurred with large amounts of cranberry juice (3 cups daily).

Case reports

  • Increased International Normalized Ratio (INR) and/or bleeding: Several cases were due to suspected interactions between cranberry juice and warfarin.

  • Internal hemorrhage resulting in death: In 2 patients, following concurrent use of warfarin and cranberry juice.

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For Healthcare Professionals

Scientific Name

Vaccinium macrocarpon

Clinical Summary

Cranberry is an evergreen shrub that is grown in North America and Europe. The processed fruit and juice, both rich in vitamin C, are widely consumed as food. The juice extract is marketed as a dietary supplement for urinary tract health and to prevent urinary tract infections (UTIs). It has also been used for oral and gastrointestinal infections, cardiovascular diseases, and against cancer.

Cranberry juice extracts and constituents exhibit antibacterial (1), antimicrobial (45), antifungal (46), anti-inflammatory (47), antioxidant (48), and antiadherence (49) properties.

Results with cranberry preparations for UTIs have been mixed. Clinical studies demonstrate that cranberry extracts can help prevent UTIs in adults (2) (3), children (4), and prostate cancer patients undergoing radiation therapy (5) (50). While a large double-blind study of older adults with high-baseline UTI risk also suggest some benefit (51), another similar study yielded negative results (52). A subsequent analysis determined there were increased costs with no meaningful reduction in UTI rates in a geriatric nursing home environment (53). Studies of cranberry juice for recurrent UTIs have also been mixed, with one study finding no benefit among college-aged women (6), and another observing significant reductions in UTI relapse in women over age 50 (54). Cranberry was not as effective or cost-effective as trimethoprim-sulfamethoxazole in preventing UTIs in premenopausal women, but patients were less likely to develop antibiotic-resistant bacteria (8) (55). In volunteers from different regions, anti-adhesion activity with cranberry powder was found to be dose-dependent (7) . Overall, a systematic review determined that cranberry juice was more effective than capsules or tablets  (56), but despite some support for recurrent UTI prophylaxis, there is not enough evidence to recommend cranberry juice for UTI prevention (9).

Cranberry juice inhibited the adhesion of H. pylori to human gastric mucosa (18), and regular consumption of cranberry juice can suppress H. pylori infection (19) (20), a major factor in peptic ulcer disease and gastric cancer. When used with standard treatment, cranberry juice helps to eradicate H. pylori in women (21). It has also been shown to prevent plaque formation and the development of gum disease due to its anticolonizing and antiadhesion properties (22) (23).

In vitro studies of cranberry extracts and proanthocyanidins demonstrate antiproliferative effects against prostate (10) (11) (12), liver (13), lung (57), neuroblastoma (58), breast (14), ovarian (15), gastric (59), colon (12) (16), esophageal (60), and oral (12) cancer cell lines. Although cranberry juice consumption did not lower oxidative status in humans, suggesting lack of protective effect against cancer or heart disease (17), it did appear to improve cardiovascular disease (CVD) risk factors in a randomized double-blind trial of diabetic men (61).

Cranberry juice has relatively high concentrations of oxalate, a common component of kidney stones, and should therefore be limited in patients with a history of nephrolithiasis (40). Other data suggest it may be helpful in more uncommon forms including struvite stones, which are associated with bladder infections (33) (62) (63) .

Food Sources

Cranberry can be consumed as juice, sauce, or dried fruit.

Purported Uses

  • Urinary tract infections
  • Cancer prevention and treatment
  • Ulcers
  • Atherosclerosis
  • Gum disease

Mechanism of Action

In vitro, cranberry proanthocyanidins (C-PACs) inhibit adherence of E. coli fimbriae to uroepithelial cells (1). A-type linkages in these C-PACs may enhance urinary bacterial antiadhesion activities to prevent UTIs (25) (26) (27) (28) (64). Similarly, activity against C. albicans biofilm formation by C-PAC is due to antiadherence properties and/or iron chelation (46). In susceptible populations, improved preventive effects with cranberry juice over capsules or tablets may be related to better hydration with liquid, and/or additive effects with additional compounds in juice not contained in supplements (56).

Antiadhesion properties are also demonstrated in other microenvironments. Cranberry prevents H. pylori-induced stomach ulcers by inhibiting bacterial adhesions in the stomach lining (18) (29). It also decreased adherence of oral streptococci strains to saliva-coated hydroxyapatite (23) and glucan-coated hydroxyapatite, and impaired biofilm formation (22) (30) indicating it may slow dental plaque development and protect against plaque-related diseases. Cranberry may regulate aggressive human periodontitis fibroblast inflammatory responses via nuclear factor-kappaB and matrix metalloproteinase-3 (MMP3) inhibition (47).

C-PACs may also play a role in enhancing host innate immunity. In a worm model, a standardized cranberry extract mediated host immune response via p38 MAPK signaling, insulin/insulin-like growth factor 1 signaling, and heat shock factor 1 (45).

Antiatherogenic effects with cranberry juice occur through decreases in serum glucose and apoB, and increases in serum and apoA-1 and paraoxonase, associated with stabilizing HDL (61).

In vitro, anticancer effects with cranberry extracts and C-PACs have been attributed to a number of mechanisms. Cranberry extract inhibited prostate cancer cell growth by decreasing cyclins, cyclin-dependant kinase expression (10) , and MMP activity (31). Dose-response inhibition of gastric cancer cells is in part due to decreased proliferating cell nuclear antigen expression and apoptotic induction (59). A proanthocyanidin isolate from cranberry may arrest ovarian cancer cell growth by inhibiting vascular endothelial growth factor and generating reactive oxygen species (15). C-PACs induced cell death in esophageal adenocarcinoma via microRNA modifications within cancer cells (60). In human lung cancer cells, C-PACs also altered gene expression, induced apoptosis, and modulated cell-cycle processes (57). In high-risk neuroblastoma cells, a purified C-PAC induced apoptosis and ROS generation, and encouraged cyclophosphamide retention with synergistic cytotoxic benefits (58).

Increased risk of uric acid stone formation with cranberry juice results from its acidifying effect and slowing of urate synthesis, decreasing urinary pH (32) (33).


• Cranberry products can increase urine oxalate excretion and may promote the formation of the most common type of kidney stones (32) (33) (40). Its use should therefore be limited in patients with a history of nephrolithiasis (40).

Adverse Reactions

Ingesting large amounts of cranberry juice (3 cups daily) has been associated with gastrointestinal upset including nausea, vomiting, and diarrhea (66).

Case Reports

Recurrent stones: In a 47-year-old man with severe right renal colic and hematuria who took cranberry concentrate tablets twice daily over 6 months (40).

Several cases of increased International Normalized Ratio (INR): Due to suspected interactions between warfarin and cranberry juice (36) (37).

Internal hemorrhage and subsequent death: In 2 patients with concurrent use of warfarin and cranberry juice (38) (39).

Herb-Drug Interactions

Warfarin: Cranberry juice may potentiate warfarin-induced anticoagulation, but data are conflicting (34) (41) (65). Although consumption of cranberry juice in large quantities (1–2 L daily or supplements for >3–4 weeks) may alter warfarin effects, monitoring intake rather than total avoidance of cranberry juice by warfarin users in other cases may be warranted (67).

Cyclosporin: A randomized controlled trial has shown that 240 mL of cranberry juice had no clinically significant effect on the disposition of a 200 mg dose of cyclosporin (42).

UGT (Uridine 5’-diphospho-glucuronosyltransferase) substrates: Cranberry modulates UGT enzymes in vitro and can increase risk of side effects of drugs metabolized by them (35).

Cytochrome P450 substrates: Cranberry inhibits enteric CYP3A activities and may interfere with the absorption of substrate drugs (43). Cranberry inhibits CYP2C9 in vitro, but this activity was not observed in humans (44).

Herb Lab Interactions

Urinary pH has been shown to decrease after drinking cranberry juice (32) (33).

Dosage (OneMSK Only)


  1. Ferrara P, Romaniello L, Vitelli O, et al. Cranberry juice for the prevention of recurrent urinary tract infections: a randomized controlled trial in children. Scand J Urol Nephrol. 2009;43(5):369-372.

  2. Barbosa-Cesnik C, Brown MB, Buxton M, et al. Cranberry juice fails to prevent recurrent urinary tract infection: results from a randomized placebo-controlled trial. Clin Infect Dis. Jan 1 2011;52(1):23-30.

  3. Jepson RG, Williams G, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2012;10:CD001321.

  4. Ferguson PJ, Kurowska E, Freeman DJ, et al. A flavonoid fraction from cranberry extract inhibits proliferation of human tumor cell lines. J Nutr. Jun 2004;134(6):1529-1535.

  5. Sun J, Chu YF, Wu X, et al. Antioxidant and antiproliferative activities of common fruits. J Agric Food Chem. Dec 4 2002;50(25):7449-7454.

  6. Kim KK, Singh AP, Singh RK, et al. Anti-angiogenic activity of cranberry proanthocyanidins and cytotoxic properties in ovarian cancer cells. Int J Oncol. Jan 2012;40(1):227-235.

  7. Parry J, Su L, Moore J, et al. Chemical compositions, antioxidant capacities, and antiproliferative activities of selected fruit seed flours. J Agric Food Chem. May 31 2006;54(11):3773-3778.

  8. Burger O, Ofek I, Tabak M, et al. A high molecular mass constituent of cranberry juice inhibits helicobacter pylori adhesion to human gastric mucus. FEMS Immunol Med Microbiol. Dec 2000;29(4):295-301.

  9. Gotteland M, Andrews M, Toledo M, et al. Modulation of Helicobacter pylori colonization with cranberry juice and Lactobacillus johnsonii La1 in children. Nutrition. May 2008;24(5):421-426.

  10. Yamanaka A, Kimizuka R, Kato T, et al. Inhibitory effects of cranberry juice on attachment of oral streptococci and biofilm formation. Oral Microbiol Immunol. Jun 2004;19(3):150-154.

  11. Neto CC. Cranberry and its phytochemicals: a review of in vitro anticancer studies. J Nutr. Jan 2007;137(1 Suppl):186S-193S.

  12. Howell AB, Reed JD, Krueger CG, et al. A-type cranberry proanthocyanidins and uropathogenic bacterial anti-adhesion activity. Phytochemistry. Sep 2005;66(18):2281-2291.

  13. Howell AB, Vorsa N, Der Marderosian A, et al. Inhibition of the adherence of P-fimbriated Escherichia coli to uroepithelial-cell surfaces by proanthocyanidin extracts from cranberries. New Engl J Med. Oct 8 1998;339(15):1085-1086.

  14. Burger O, Weiss E, Sharon N, et al. Inhibition of Helicobacter pylori adhesion to human gastric mucus by a high-molecular-weight constituent of cranberry juice. Crit Rev Food Sci Nutr. 2002;42(3 Suppl):279-284.

  15. Koo H, Nino de Guzman P, Schobel BD, et al. Influence of cranberry juice on glucan-mediated processes involved in Streptococcus mutans biofilm development. Caries Res. 2006;40(1):20-27.

  16. Gettman MT, Ogan K, Brinkley LJ, et al. Effect of cranberry juice consumption on urinary stone risk factors. J Urol. Aug 2005;174(2):590-594; quiz 801.

  17. Greenblatt DJ, von Moltke LL, Perloff ES, et al. Interaction of flurbiprofen with cranberry juice, grape juice, tea, and fluconazole: in vitro and clinical studies. Clin Pharm Ther. Jan 2006;79(1):125-133.

  18. Hamann GL, Campbell JD, George CM. Warfarin-cranberry juice interaction. Ann Pharmacother. Mar 2011;45(3):e17.

  19. Roberts D, Flanagan P. Case report: Cranberry juice and warfarin. Home Healthc Nurse. Feb 2011;29(2):92-97.

  20. Griffiths AP, Beddall A, Pegler S. Fatal haemopericardium and gastrointestinal haemorrhage due to possible interaction of cranberry juice with warfarin. J R Soc Promot Health. Nov 2008;128(6):324-326.

  21. Suvarna R, Pirmohamed M, Henderson L. Possible interaction between warfarin and cranberry juice. BMJ. Dec 20 2003;327(7429):1454.

  22. Mohammed Abdul MI, Jiang X, Williams KM, et al. Pharmacodynamic interaction of warfarin with cranberry but not with garlic in healthy subjects. Brit J Pharmacol. Aug 2008;154(8):1691-1700.

  23. Grenier J, Fradette C, Morelli G, et al. Pomelo juice, but not cranberry juice, affects the pharmacokinetics of cyclosporine in humans. Clin Pharm Ther. Mar 2006;79(3):255-262.

  24. Ushijima K, Tsuruoka S, Tsuda H, et al. Cranberry juice suppressed the diclofenac metabolism by human liver microsomes, but not in healthy human subjects. Brit J Clin Pharmacol. Aug 2009;68(2):194-200.

  25. Tipton DA, Babu JP, Dabbous M. Effects of cranberry components on human aggressive periodontitis gingival fibroblasts. J Periodontal Res. Aug 2013;48(4):433-442.

  26. Girardot M, Guerineau A, Boudesocque L, et al. Promising results of cranberry in the prevention of oral Candida biofilms. Pathog Dis. Apr 2014;70(3):432-439.

  27. Juthani-Mehta M, Van Ness PH, Bianco L, et al. Effect of Cranberry Capsules on Bacteriuria Plus Pyuria Among Older Women in Nursing Homes: A Randomized Clinical Trial. JAMA. 2016 Oct 27. doi: 10.1001/jama.2016.16141.

  28. Liu M, Lin LQ, Song BB, et al. Cranberry phytochemical extract inhibits SGC-7901 cell growth and human tumor xenografts in Balb/c nu/nu mice. J Agric Food Chem. Jan 28 2009;57(2):762-768.

  29. Shidfar F, Heydari I, Hajimiresmaiel SJ, et al. The effects of cranberry juice on serum glucose, apoB, apoA-I, Lp(a), and Paraoxonase-1 activity in type 2 diabetic male patients. J Res Med Sci. Apr 2012;17(4):355-360.

  30. Frassetto L, Kohlstadt I. Treatment and prevention of kidney stones: an update. Am Fam Physician. Dec 1 2011;84(11):1234-1242.

  31. Preventing kidney stones with diet and nutrition. Am Fam Physician. Dec 1 2011;84(11):1243-1244.

  32. Krueger CG, Reed JD, Feliciano RP, et al. Quantifying and characterizing proanthocyanidins in cranberries in relation to urinary tract health. Anal Bioanal Chem. May 2013;405(13):4385-4395.

  33. Ansell J, McDonough M, Zhao Y, et al. The absence of an interaction between warfarin and cranberry juice: a randomized, double-blind trial. J Clin Pharmacol. Jul 2009;49(7):824-830.

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