Fruit Juice
The original and most-studied form, taken as pure or concentrated cranberry juice.
Juice · Concentrate
EU Health Claim Recognised · Directive 2002/46/CE
Biological Overview
Vaccinium macrocarpon is an evergreen shrub of the Ericaceae family that grows in peat bogs and mountain forests, native exclusively to North America. It is now cultivated industrially in sandy flooded beds called cranberry bogs, producing dark red, tart, spherical berries 1–2 cm in diameter. A related but botanically distinct species, Vaccinium oxycoccos, grows in Europe and temperate Asia — its use is not validated for urinary tract infection prevention.
FamilyEricaceae
Berry Size1–2 cm
Key CompoundA-Type PACs
Usual PAC Dose36 mg
Botanical Classification
Taxonomy & Identification
- Latin Name
- Vaccinium macrocarpon Aiton
- Related Species
- V. oxycoccos L. (European, not validated)
- Family
- Ericaceae
- Common Names
- Cranberry, Canneberge, Atoca, Airelle
- Parts Used
- Fruit, fruit juice
- Origin
- North American peat bogs & sandy meadows
⚠ Two Species, Not One
Vaccinium macrocarpon, the large-fruited American cranberry, is the species behind virtually all documented research in this monograph. The European cranberry, Vaccinium oxycoccos, is a related but distinct species whose use for urinary tract infection prevention is explicitly not validated by the primary source.
Ethnobotany & Traditional Use
History & Tradition
The old American name for the plant, "crane-berry," means "crane's berry" — early in the flowering season, the flowers droop toward the ground, giving the plant the appearance of a crane's head and neck.
Modern scientific interest accelerated once researchers identified that a specific epicatechol trimer, rather than the once-assumed mechanism of urine acidification, was responsible for preventing bacterial adhesion to the bladder wall — a finding that redirected decades of cranberry research toward its proanthocyanidin content specifically.
The Key Molecule
Proanthocyanidins (PACs) — Deep Dive
A-type proanthocyanidins, condensed tannin polymers of epicatechol, are the compounds behind cranberry's signature anti-adhesion mechanism.
🎯
🧬
🏅
First EU Health Claim for a Botanical
AFSSA granted a health claim under EU Directive 2002/46/CE in April 2004 — the first time granted for a plant ingredient, specifically for Vaccinium macrocarpon. [8]
⚖️
Standardized to 36 mg PAC
The dose used in the source's own usual dosage guidance and in most PAC-standardized commercial extracts and clinical trials.
Pharmaceutical Preparations
Parts Used & Available Forms
The fruit and fruit juice are the parts used, across juice, dry extract and powder preparations.
Standardized Dry Extract
Dry extract of the fruit, standardized to PAC content — the form used in most modern capsule supplements.
Dry Extract · Standardized
Fruit Powder
Whole fruit powder, an unstandardized alternative to juice or extract capsules.
Powder
Clinical Dosimetry
Dosages
Traditional and standardized dosing across juice, concentrate and dry extract forms, per the primary source.
Phytochemistry
Composition
Documented phytochemistry of the fruit, the sole part with a described composition in the primary source.
Simple SugarsFructose, glucose, saccharose, above all D-mannose
Present
Organic AcidsBenzoic, ascorbic (vitamin C), citric, malic and quinic acids; hydroxycinnamic and other phenolic acids
Present
PolyolsDocumented polyol fraction
Present
Anthocyanosides3-O-arabinosyl-peonidol
Present
Flavonoids & PectinsFlavanols, flavonols, pectins
Present
Proanthocyanidols (PACs)Condensed tannins — dimers, trimers, pentamers and tetramers of epicatechol
Key Compound
Trans-ResveratrolStilbenoid compound
Present
🦠
Antibacterial (Intestinal & Urinary)
Inhibits adhesion of E. coli to bladder and intestinal walls, likely via the same mechanism documented in related Vaccinium species.
🧬
Anti-Adhesion (Specific Trimer)
A specific epicatechol trimer prevents bacterial adhesion to the bladder wall — the mechanism once mistakenly attributed to urine acidification.
🎯
P-Fimbriae Synthesis Inhibition
A-type PACs inhibit P-fimbriae (pili) synthesis on vaginal and bladder walls and deform the bacteria, in both antibiotic-sensitive and resistant strains. [3][7]
🏅
First EU Health Claim for a Botanical
AFSSA granted a health claim in April 2004 under EU Directive 2002/46/CE — the first time granted for a plant ingredient. [8]
🦠
Anti-H. pylori
Inhibits growth of Helicobacter pylori, with synergy alongside marjoram via likely urease and proline dehydrogenase inhibition. [9][10]
🦷
Periodontal Protection
Inhibits acid production, adhesion and biofilm formation by Streptococcus mutans; inhibits inflammation and matrix-destroying enzyme activity from Porphyromonas gingivalis. [11]
🧫
Anti-Biofilm Activity
Documented anti-biofilm properties against Pseudomonas aeruginosa. [12]
💊
Antistaphylococcal
Antistaphylococcal activity that potentiates the efficacy of beta-lactam antibiotics. [13]
🍄
Anti-Candida
Opposes adhesion of Candida albicans to mucosal surfaces. [17]
🧬
Anticancer Potential
Documented anticancer properties, with active compounds including ursolic acid, quercetin and a pentahydroxyflavonol glucoside. [18][19]
❤️
Cardiovascular Prevention
Documented cardiovascular disease risk factor prevention. [20]
🩺
Radiotherapy-Related UTI Prevention
Reduces urinary tract infection risk during radiotherapy for prostate carcinoma. [22]
Clinical Applications
Clinical Indications
Traditional and researched uses, alongside the regulatory nuance the primary source itself documents.
🩺
Urinary Tract Infection Prevention
Primary Indication
🦷
Oral Health
Candidiasis & Periodontal Disease
- Oral candidiasis: documented traditional and researched indication.
- Periodontal disease: documented traditional indication tied to anti-biofilm activity.
🩹
Gastrointestinal
H. pylori-Related Conditions
- Ulcers & H. pylori-related gastritis: preventive indication. [33]
❔
Mixed Clinical Results
Population-Dependent Findings
- Elderly nursing-home residents: in women with bacteriuria and pyuria, cranberry capsules (36 mg PAC/day) for one year showed no significant difference from placebo. [27]
⚠ Regulatory Caution: Mechanism ≠ Proven Prevention
European regulators draw a careful distinction
Both EFSA (2009) and ANSES (2011) concluded that cranberry PAC activity against E. coli adhesion to urinary epithelial cells via P-fimbriae is well demonstrated in laboratory research, but that available data do not allow a conclusive determination that cranberry consumption prevents urinary tract infections in practice. Both agencies agree that consumption poses no risk to the general population. [34][35]
Pharmacodynamics
Mode of Action
The documented mechanism behind cranberry's anti-adhesion activity.
🧬
Bacterial Anti-Adhesion to Uroepithelial Cells
Proanthocyanidols — especially epicatechol trimers, tannins common in the fruit — inhibit bacterial adhesion to uroepithelial cells, the central mechanism behind cranberry's documented urinary activity.
⚖️
Effective Dose
This anti-adhesion effect is documented at a dose of 36 mg of proanthocyanidins, the standard used across most clinical research and commercial extracts.
Clinical Safety
Safety, Interactions & Precautions
Documented contraindications, drug interactions and precautions for fruit and juice preparations.
Adverse Effects
Drug Interactions
- Warfarin: suspected CYP2C9 inhibition and potentiation of anticoagulation; a pharmacokinetic interaction is considered improbable, but patients on warfarin with cranberry juice should be alerted and monitor for bleeding signs and symptoms. [37][38]
- Cytochrome P450 (general): inhibition of CYP450 enzymatic activity by a cranberry flavonoid has not been demonstrated. [36]
Clinical Disclaimer: This monograph is for educational and professional reference only. It does not constitute medical advice, diagnosis, or treatment guidance. Always consult a qualified healthcare provider before initiating any phytotherapeutic regimen, particularly if you are taking prescription medications, are pregnant, or have existing health conditions.
Common Questions
Frequently Asked Questions
What is cranberry traditionally used for?
Cranberry (Vaccinium macrocarpon) fruit and fruit juice are primarily used for preventing urinary tract infections, especially those caused by Escherichia coli, and possibly reducing the risk of kidney stones.
Which part of the cranberry plant is used medicinally?
The fruit and fruit juice are the parts used, available as juice, dry extract, or fruit powder.
What are proanthocyanidins (PACs) and why do they matter in cranberry?
Proanthocyanidins are condensed tannins, polymers of epicatechol, found in cranberry fruit. A-type PACs specifically inhibit the synthesis of P-fimbriae (adhesion pili) on bacteria, preventing them from sticking to bladder and vaginal walls, and can deform the bacteria themselves. The usual standardized dose is 36 mg of PACs.
Does cranberry actually prevent UTIs, or is the evidence mixed?
The evidence is genuinely mixed. Systematic reviews and meta-analyses have found that cranberry products reduce the incidence of urinary tract infections in susceptible populations. However, European regulatory agencies (EFSA in 2009, ANSES in 2011) concluded that while cranberry's anti-adhesion mechanism against E. coli is well demonstrated, available data do not allow a definitive conclusion that cranberry consumption prevents urinary tract infections. One randomized trial in elderly women in nursing homes with bacteriuria and pyuria found no significant difference between cranberry capsules and placebo over one year.
Is European cranberry the same as American cranberry?
No. Vaccinium macrocarpon, the large-fruited American cranberry, is native only to North America and is the species with validated research for urinary tract infection prevention. The European cranberry, Vaccinium oxycoccos, grows in Europe and temperate Asia, but its use is not validated for preventing urinary infections.
Can cranberry interact with warfarin?
There is a suspected interaction: cranberry may inhibit the CYP2C9 enzyme and potentiate warfarin's anticoagulant effect, though a pharmacokinetic interaction is considered improbable. As a precaution, patients taking warfarin alongside cranberry juice should be alerted to the potential interaction and monitor for signs and symptoms of bleeding.
Is cranberry safe to use during pregnancy?
Yes. Research has found no contraindication to cranberry use during pregnancy, and no increased risk of malformations, neonatal mortality, preterm birth, low birth weight, low Apgar score, or neonatal infections.
Can cranberry increase the risk of kidney stones?
There is a theoretical risk of increased urinary elimination of calcium oxalate with cranberry use, which is relevant for people prone to oxalate-based kidney stones.
Primary Literature
Bibliography
↑1. Pappas E, Schaich KM. Phytochemicals of cranberries and cranberry products: characterization, potential health effects, and processing stability. Crit Rev Food Sci Nutr. 2009 Oct;49(9):741-81. PubMed PMID:20443158 →
↑2. Wang Y, Catana F, Yang Y, Roderick R, van Breemen RB. An LC-MS method for analyzing total resveratrol in grape juice, cranberry juice, and in wine. J Agric Food Chem. 2002;50:431-5. PubMed PMID:11804508 →
↑3. Howell AB, Reed JD, Krueger CG, Winterbottom R, Cunningham DG, Leahy M. A-type cranberry proanthocyanidins and uropathogenic bacterial anti-adhesion activity. Phytochemistry. 2005 Sep;66(18):2281-91. PubMed PMID:16055161 →
↑4. Foo LY, Lu Y, Howell AB, Vorsa N. The structure of cranberry proanthocyanidins which inhibit adherence of uropathogenic P-fimbriated Escherichia coli in vitro. Phytochemistry. 2000 May;54(2):173-81. PubMed PMID:10872208 →
↑5. Gupta K, Chou MY, Howell A, Wobbe C, Grady R, Stapleton AE. Cranberry products inhibit adherence of p-fimbriated Escherichia coli to primary cultured bladder and vaginal epithelial cells. J Urol. 2007 Jun;177(6):2357-60. PubMed PMID:17509358 →
↑6. Foo LY, Lu Y, Howell AB, Vorsa N. A-type proanthocyanidin trimers from Cranberries that inhibit adherence of uropathogenic P-fimbriated Escherichia coli. J Nat Prod. 2000;63:1225-1228. PubMed PMID:11000024 →
↑7. Lavigne JP, et al. Cranberry (Vaccinium macrocarpon) and urinary tract infections: study model and review of literature. Pathol Biol (Paris). 2007;55(8-9):460-4.
↑8. AFSSA. Saisine n°2003-SA 0352. 2004.
↑9. Matsushima M, Suzuki T, Masui A, Kasai K, Kouchi T, Takagi A, Shirai T, Mine T. Growth inhibitory action of cranberry on Helicobacter pylori. J Gastroenterol Hepatol. 2008 Dec;23 Suppl 2:S175-80. PubMed PMID:19120894 →
↑10. Lin YT, Kwon YI, Labbe RG, Shetty K. Inhibition of Helicobacter pylori and Associated Urease by Oregano and Cranberry Phytochemical Synergies. Appl Environ Microbiol. 2005 Dec;71(12):8558-8564. Full Text →
↑11. La VD, Howell AB, Grenier D. Anti-Porphyromonas gingivalis and anti-inflammatory activities of A-type cranberry proanthocyanidins. Antimicrob Agents Chemother. 2010 May;54(5):1778-84. PubMed PMID:20176905 →
↑12. Ulrey RK, Barksdale SM, Zhou W, van Hoek ML. Cranberry proanthocyanidins have anti-biofilm properties against Pseudomonas aeruginosa. BMC Complement Altern Med. 2014;14:499. Abstract →
↑13. Diarra MS, Block G, Rempel H, Oomah BD, Harrison J, McCallum J, Boulanger S, Brouillette É, Gattuso M, Malouin F. In vitro and in vivo antibacterial activities of cranberry press cake extracts alone or in combination with beta-lactams against Staphylococcus aureus. BMC Complement Altern Med. 2013;13:90. Abstract →
↑14. Zhang L, Ma J, Pan K, Go VL, Chen J, You WC. Efficacy of cranberry juice on Helicobacter pylori infection: a double-blind, randomized placebo-controlled trial. Helicobacter. 2005 Apr;10(2):139-45. PubMed PMID:15810945 →
↑15. Matsushima M, Suzuki T, Masui A, Kasai K, Kouchi T, Takagi A, Shirai T, Mine T. Growth inhibitory action of cranberry on Helicobacter pylori. J Gastroenterol Hepatol. 2008 Dec;23 Suppl 2:S175-80. PubMed PMID:19120894 →
↑16. Shmuely H, Yahav J, Samra Z, Chodick G, Koren R, Niv Y, Ofek I. Effect of cranberry juice on eradication of Helicobacter pylori in patients treated with antibiotics and a proton pump inhibitor. Mol Nutr Food Res. 2007 Jun;51(6):746-51. PubMed PMID:17487928 →
↑17. Feldman M, Tanabe S, Howell A, Grenier D. Cranberry proanthocyanidins inhibit the adherence properties of Candida albicans and cytokine secretion by oral epithelial cells. BMC Complement Altern Med. 2012. Full Text →
↑18. Côté J, Caillet S, Doyon G, Sylvain JF, Lacroix M. Bioactive compounds in cranberries and their biological properties. Crit Rev Food Sci Nutr. 2010 Aug;50(7):666-79. PubMed PMID:20694928 →
↑19. He X, Liu RH. Cranberry phytochemicals: Isolation, structure elucidation, and their antiproliferative and antioxidant activities. J Agric Food Chem. 2006 Sep 20;54(19):7069-74. PubMed PMID:16968064 →
↑20. McKay DL, Blumberg JB. Cranberries (Vaccinium macrocarpon) and cardiovascular disease risk factors. Nutr Rev. 2007 Nov;65(11):490-502. PubMed PMID:18038941 →
↑21. Jepson RG, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2008 Jan 23;(1):CD001321. PubMed PMID:18253990 →
↑22. Bonetta A, Di Pierro F. Enteric-coated, highly standardized cranberry extract reduces risk of UTIs and urinary symptoms during radiotherapy for prostate carcinoma. Cancer Manag Res. 2012;4:281-6. PubMed PMID:22977312 →
↑23. 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. 2017 Sep;198(3):614-621. PubMed PMID:28288837 →
↑24. Xia JY, Yang C, Xu DF, Xia H, Yang LG, Sun GJ. Consumption of cranberry as adjuvant therapy for urinary tract infections in susceptible populations: A systematic review and meta-analysis with trial sequential analysis. PLoS One. 2021 Sep 2;16(9):e0256992. PubMed PMID:34473789 →
↑25. Babar A, Moore L, Leblanc V, Dudonné S, Desjardins Y, Lemieux S, Bochard V, Guyonnet D, Dodin S. High dose versus low dose standardized cranberry proanthocyanidin extract for the prevention of recurrent urinary tract infection in healthy women: a double-blind randomized controlled trial. BMC Urol. 2021 Mar 23;21(1):44. PubMed PMID:33757474 →
↑26. Asma B, Vicky L, Stephanie D, Yves D, Amy H, Sylvie D. Standardised high dose versus low dose cranberry Proanthocyanidin extracts for the prevention of recurrent urinary tract infection in healthy women [PACCANN]: a double blind randomised controlled trial protocol. BMC Urol. 2018 May 2;18(1):29. PubMed PMID:29716563 →
↑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 Nov 8;316(18):1879-1887. PubMed PMID:27787564 →
↑28. Manges AR, Smith SP, Lau BJ, Nuval CJ, Eisenberg JN, Dietrich PS, Riley LW. Retail meat consumption and the acquisition of antimicrobial resistant Escherichia coli causing urinary tract infections: a case-control study. Foodborne Pathog Dis. 2007 Winter;4(4):419-31. PubMed PMID:18041952 →
↑29. Johnson JR, Delavari P, O'Bryan TT, Smith KE, Tatini S. Contamination of retail foods, particularly turkey, from community markets (Minnesota, 1999-2000) with antimicrobial-resistant and extraintestinal pathogenic Escherichia coli. Foodborne Pathog Dis. 2005 Spring;2(1):38-49. PubMed PMID:15992297 →
↑30. Smith JL, Fratamico PM, Gunther NW. Extraintestinal pathogenic Escherichia coli. Foodborne Pathog Dis. 2007 Summer;4(2):134-63. PubMed PMID:17600482 →
↑31. Bélanger L, Garenaux A, Harel J, Boulianne M, Nadeau E, Dozois CM. Escherichia coli from animal reservoirs as a potential source of human extraintestinal pathogenic E. coli. FEMS Immunol Med Microbiol. 2011 Jun;62(1):1-10. PubMed PMID:21362060 →
↑32. Foley SL, Lynne AM. Food animal-associated Salmonella challenges: pathogenicity and antimicrobial resistance. J Anim Sci. 2008 Apr;86(14 Suppl):E173-87. PubMed PMID:17878285 →
↑33. Li ZX, Ma JL, Guo Y, et al. Suppression of Helicobacter pylori infection by daily cranberry intake: A double-blind, randomized, placebo-controlled trial. J Gastroenterol Hepatol. 2021 Apr;36(4):927-935. PubMed PMID:32783238 →
↑34. EFSA. Scientific Opinion on the substantiation of health claims related to proanthocyanidins from cranberry (Vaccinium macrocarpon Aiton) fruit and defence against bacterial pathogens in the lower urinary tract. Full Text →
↑35. ANSES. Avis relatif à l'évaluation des effets potentiels de la canneberge dans le champ des infections urinaires communautaires. Full Text →
↑36. Suvarna R, Pirmohamed M, Henderson L. Possible interaction between warfarin and cranberry juice. BMJ. 2003;327(7429):1454.
↑37. Greenblatt DJ, von Moltke LL, Perloff ES, Luo Y, Harmatz JS, Zinny MA. Interaction of flurbiprofen with cranberry juice, grape juice, tea, and fluconazole: in vitro and clinical studies. Clin Pharmacol Ther. 2006 Jan;79(1):125-33. PubMed PMID:16413247 →
↑38. Pham DQ, Pham AQ. Interaction potential between cranberry juice and warfarin. Am J Health Syst Pharm. 2007 Mar 1;64(5):490-4. PubMed PMID:17322161 →
↑39. Dugoua JJ, Seely D, Perri D, Mills E, Koren G. Safety and efficacy of cranberry (vaccinium macrocarpon) during pregnancy and lactation. Can J Clin Pharmacol. 2008 Winter;15(1):e80-6. PubMed PMID:18204103 →
↑40. Heitmann K, Nordeng H, Holst L. Pregnancy outcome after use of cranberry in pregnancy — the Norwegian mother and child cohort study. BMC Complement Altern Med. 2013;13:345. Full Text →
Additional Reference Literature
Avorn J, et al. Reduction of Bacteruria and Pyuria after ingestion of Cranberry Juice. JAMA. 1994 Mar 9;271(10):751-4.
Howell AB, Foxman B. Cranberry juice and adhesion of antibiotic-resistant uropathogens. JAMA. 2002 Jun 19;287(23):3082-3.
Howell A. Cranberry proanthocyanidins and the maintenance of urinary tract health. Crit Rev Food Sci Nutr. 2002;42(3 Suppl):273-8. PubMed PMID:12058985 →
Howell AB. Bioactive compounds in cranberries and their role in prevention of urinary tract infections. Mol Nutr Food Res. 2007 Jun;51(6):732-7. PubMed PMID:17487930 →
Jepson RG, Mihaljevic L, Craig J. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2004;(1). PubMed PMID:18253990 →
Jepson RG, Craig JC. A systematic review of the evidence for cranberries and blueberries in UTI prevention. Mol Nutr Food Res. 2007 Jun;51(6):738-45. PubMed PMID:17492798 →
Jepson RG, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2008 Jan 23;(1):CD001321. PubMed PMID:18253990 →
Kontiokari T, Salo J, Eerola E, Uhari M. Cranberry juice and bacterial colonization in children — a placebo-controlled randomized trial. Clin Nutr. 2005 Dec;24(6):1065-72. PubMed PMID:16194582 →
Kontiokari T, Sundqvist K, Nuutinen M, Pokka T, Koskela M, Uhari M. Randomised trial of cranberry-lingonberry juice and Lactobacillus GG drink for the prevention of urinary tract infections in women. BMJ. 2001 Jun 30;322(7302):1571. PubMed PMID:11431298 →
Lavigne JP, Bourg G, Combescure C, Botto H, Sotto A. In-vitro and in-vivo evidence of dose-dependent decrease of uropathogenic Escherichia coli virulence after consumption of commercial Vaccinium macrocarpon (cranberry) capsules. Clin Microbiol Infect. 2008 Apr;14(4):350-5. PubMed PMID:18190583 →
Leahy M, Roderick R, Brilliant K. The Cranberry — Promising Health Benefits, Old and New. Nutrition Today. 2001;36(5):254-265.
Schmidt DR, Sobota AE. An examination of the anti-adherence activity of cranberry juice on urinary and nonurinary bacterial isolates. Microbios. 1988;55(224-225):173-81. PubMed PMID:3063927 →
Stothers L. A randomized trial to evaluate effectiveness and cost effectiveness of naturopathic cranberry products as prophylaxis against urinary tract infection in women. Lan J Urol. 2002 Jun;9(3):1558-62.
Stothers L. Dose-response of cranberry in women with recurrent UTIs. CRISP, Grant number: 5R0lAT002090-03.
Turner A, Chen SN, Joike MK, Pendland SL, Pauli GF, Farnsworth NR. Inhibition of uropathogenic Escherichia coli by cranberry juice: a new antiadherence assay. J Agric Food Chem. 2005 Nov 16;53(23):8940-7. PubMed PMID:16277386 →
Zafriri D, Ofek I, Adar R, Pocino M, Sharon N. Inhibitory activity of cranberry juice on adherence of type 1 and type P fimbriated Escherichia coli to eucaryotic cells. Antimicrob Agents Chemother. 1989 Jan;33(1):92-8. PubMed PMID:2653218 →