A fresh cranberry bounces. Small air-filled chambers inside the berry make it bounce and float. Growers use that at harvest: the beds are flooded in autumn and the berries rise to the surface. The beds are not underwater all year, a common misconception.
Hardly anyone eats cranberries the way they grow. About 95% are made into juice, sauce or sweetened dried fruit, because a raw berry is hard, sour and bitter.
Raw, they hold 46 calories and 4.3 g of sugar per 100 g. USDA lists 11.9 g of sugar per 100 g for bottled cranberry juice cocktail and 72.6 g for sweetened dried cranberries. The form matters, so each study below says which one it used.
The famous research is about urinary tract infections. In 2000, chemists isolated A-type proanthocyanidins from cranberries that stopped E. coli from the urinary tract sticking to cells in the lab. That idea set off decades of trials with mixed results. Many were funded or supplied by the cranberry industry, and each card says so when the paper does.
Health benefits of cranberries
The top findings from 30 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★Fewer urinary tract infections (UTIs) with symptomsAcross 50 trials, cranberry products lowered the risk of a UTI with symptoms by about 30%, with little or no benefit in nursing home residents. Results varied, and several juice trials found no significant benefit.
- ★★Antibiotic prevented more UTIs than capsulesIn 221 women with recurrent UTIs, women on cranberry capsules had 4.0 UTIs with symptoms over 12 months, against 1.8 on the antibiotic. After 1 month, 86.3% of gut E. coli were resistant to the antibiotic in that group, against 23.7% on cranberry.
- ★★Mixed results for UTIs after pelvic surgeryOne trial of cranberry capsules after gynecologic surgery cut UTIs from 38% to 19%. Another, after pelvic floor surgery, found UTIs in 12.4% against 20.0%, not significant, and a third found no difference in urine bacteria (27% against 25%).
- ★★More H. pylori stomach infections clearedIn 522 infected adults, cranberry juice twice a day for 8 weeks cleared the stomach bacterium H. pylori in 20%, against 7.35% on placebo. Only the high-proanthocyanidin juice worked; lower doses and capsules did not.
- ★★Better cholesterol ratio, but no change in LDLIn 16 pooled trials, the total to HDL cholesterol ratio fell 0.24 and a measure of insulin resistance (HOMA-IR) fell 0.59. LDL, fasting glucose and triglycerides did not change overall.
All 30 studies, strongest evidence first
Cranberry products lowered symptomatic UTI risk about 30% across 50 trials
This Cochrane review (Cochrane reviews pool many trials) covered 50 trials with 8,857 people. The 26 trials that could be pooled (6,211 people) gave a risk ratio of 0.70, but results varied from trial to trial. Cranberry helped women with recurrent UTIs (0.74), children (0.46) and people prone to UTIs after medical procedures (0.47). There was little or no benefit in nursing home residents (0.93) and pregnant women (1.06).
Cranberry juice lowered UTI rates 27% against placebo liquid
This network meta-analysis, which compares many treatments at once, reviewed 20 trials with 3,091 people. Against no treatment the drop was 54%. Antibiotic use was 49% lower than with placebo liquid, based on 6 trials. The authors rate the certainty of the evidence as moderate to low.
In women with a past UTI, cranberry cut repeat risk 26%
This meta-analysis (a study pooling many trials) covered 7 randomized trials with 1,498 healthy women who had had a UTI. The risk ratio was 0.74, with real differences between trials. Only 2 trials had more than 300 people, and 2 had high loss to follow-up or selective reporting. One author has received grant funding from Ocean Spray, which the paper says had no role in the study.
Women after a UTI: cranberry drink meant 39 clinical UTIs versus 67
In this double-blind, placebo-controlled trial, women with a recent UTI drank one 240 mL serving of a cranberry juice beverage a day for 24 weeks. With 185 women on cranberry and 188 on placebo, the rate ratio was 0.61 after adjusting for antibiotic use. Time to a culture-confirmed UTI did not differ between the groups. Ocean Spray funded the trial, and two authors work there.
Twice-daily cranberry juice did not prevent a second UTI in college women
This double-blind, placebo-controlled trial gave 319 college women with an acute UTI 8 oz doses of 27% cranberry juice for up to 6 months. A second UTI occurred in 20.0% on cranberry juice and 14.0% on placebo. It was designed to detect a 2-fold difference. The NIH funded it, and Ocean Spray provided the juice.
Cranberry juice did not significantly reduce UTIs versus placebo juice
This randomized trial gave 176 women 4 oz or 8 oz of cranberry juice a day, or placebo juice, for a median of 168 days. The cumulative UTI rate was 0.29 on cranberry and 0.37 on placebo. Fewer women on cranberry had P-fimbriated E. coli, a sticky strain, in their urine (43.5% against 80.0%), but that gap was not statistically significant. The NIH funded it, and Ocean Spray made the juices.
A daily antibiotic prevented more UTIs than cranberry capsules
This double-blind trial included 221 premenopausal women with recurrent UTIs. They took 500 mg cranberry capsules twice a day or the antibiotic trimethoprim-sulfamethoxazole once a day. Over 12 months, women on capsules had 4.0 symptomatic UTIs, against 1.8 on the antibiotic. After 1 month, 86.3% of gut E. coli were resistant to that antibiotic in the antibiotic group, against 23.7% in the cranberry group.
Cranberry capsules did not lower bacteriuria with pyuria in older women
This double-blind, placebo-controlled trial gave 185 women aged 65 or older in 21 nursing homes two capsules a day for a year. The capsules held 72 mg of proanthocyanidins in total. Bacteriuria plus pyuria, meaning bacteria and white blood cells in the urine, occurred at adjusted rates of 29.1% on cranberry and 29.0% on placebo. Symptomatic UTIs were similar (10 episodes against 12), and the NIH funded it with capsules donated by an independent manufacturer.
In children, cranberry juice cut UTI episodes but not clearly repeat cases
This double-blind trial in 7 Finnish hospitals analyzed 255 children after a UTI, who drank cranberry juice or placebo for 6 months. A repeat UTI occurred in 16% against 22%, not a significant difference. Episodes totaled 27 on cranberry and 47 on placebo. Children on cranberry spent 6 fewer days on antibiotics per patient-year.
Cranberry capsules after gynecologic surgery cut UTIs from 38% to 19%
This double-blind, placebo-controlled trial included 160 women who had a urinary catheter after elective surgery. Over 6 weeks, 15 of 80 on cranberry capsules and 30 of 80 on placebo had a UTI (odds ratio 0.38). It ran at a single hospital. The NIH funded it, and the capsules were donated by their maker.
Cranberry proanthocyanidins did not reduce bacteriuria after pelvic surgery
This double-blind, placebo-controlled trial gave 272 women who had a urinary catheter after surgery 36 mg of cranberry proanthocyanidins a day for 10 days. Bacteriuria, bacteria in the urine, occurred in 27% on cranberry and 25% on placebo (relative risk 1.05). That differs from the result in the gynecologic surgery trial above.
Cranberry capsules did not significantly lower UTIs after pelvic floor surgery
This double-blind, placebo-controlled trial gave 105 women in each arm cranberry capsules or placebo twice a day for 6 weeks. UTIs occurred in 12.4% against 20.0%. UTI rates were lower than the authors expected in both arms, so a benefit cannot be ruled out where UTIs are more common.
In infected adults, cranberry juice cleared H. pylori in 20% versus 7.35%
This double-blind trial gave 522 adults infected with the stomach bacterium H. pylori cranberry juice twice a day for 8 weeks. Only the high-proanthocyanidin juice, with 44 mg per serving, worked; lower juice doses and cranberry powder capsules did not. The Cranberry Marketing Committee, a US cranberry industry body, funded it, and Ocean Spray supplied the placebo.
Cranberry lowered the cholesterol ratio and insulin resistance, not LDL
This meta-analysis pooled 16 trials. The total to HDL cholesterol ratio fell 0.24 and HOMA-IR, a measure of insulin resistance, fell 0.59. Total cholesterol, LDL, HDL, triglycerides, fasting glucose, HbA1c and fasting insulin did not change overall. Dried forms (capsules, powder and tablets) did lower fasting insulin.
Cranberry-lingonberry concentrate cut repeat UTIs to 16%, against 36% untreated
In this open trial in Finland, 150 women took 50 mL of cranberry-lingonberry juice concentrate a day for 6 months. The women knew what they were taking. A Lactobacillus drink did no better than no treatment (39% against 36%). Finnish foundations funded it.
A Cochrane review found no trials of cranberry to treat a UTI
The 2023 search found no randomized trials that met the review’s rules. Seven studies were excluded for reasons such as a wrong design or mixed treatments. The authors say there is no good-quality evidence that cranberry treats a UTI.
Daily cranberry juice cocktail did not significantly reduce UTIs in pregnancy
This pilot trial gave pregnant women cranberry juice cocktail three times a day, once a day or placebo. The three-times-a-day group had 6 UTIs and the placebo group 11, too few to be sure of a difference. In all, 73 of 188 women dropped out, most because of stomach upset.
After cranberry powder, urine blocked E. coli sticking up to 24 hours
In this randomized, double-blind trial, 32 volunteers took cranberry powder with 72 mg of proanthocyanidins. The effect was measured on their urine in the lab, not on infections. It grew with the dose.
Low-calorie cranberry juice lowered the inflammation marker CRP
In this double-blind trial, 56 adults on controlled diets drank two 240 mL servings a day of low-calorie cranberry juice or placebo for 8 weeks. CRP fell to 1.69 mg/L, against 2.71 mg/L on placebo. Triglycerides, diastolic blood pressure (69.2 against 71.6 mm Hg) and fasting glucose were also lower on the juice. One author works for Ocean Spray.
Double-strength cranberry juice lowered aortic stiffness in coronary artery disease
In this crossover trial, 44 people with coronary artery disease drank 480 mL a day of cranberry juice or placebo for 4 weeks. Pulse wave velocity fell from 8.3 to 7.8 m/s on the juice and rose from 8.0 to 8.4 m/s on placebo. Artery widening and blood pressure did not change. Ocean Spray funded the study.
In diabetes, sweetened dried cranberries peaked blood sugar like white bread
In this crossover test, 13 people with type 2 diabetes ate white bread (57 g), raw cranberries (55 g) or sweetened dried cranberries (40 g). They also ate a lower-sugar dried version (40 g) with a bulking agent added. Sweetened dried cranberries peaked at 9.6 mmol/L, like white bread, while raw cranberries peaked at 7.0. The lower-sugar version peaked at 8.7 mmol/L and gave a smaller insulin response than the sweetened one.
In type 2 diabetes, reduced-sugar dried cranberries lowered the blood sugar rise
In this randomized crossover trial, 25 obese adults ate a high-fat breakfast with or without 40 g of reduced-sugar dried cranberries. Blood sugar rose less at 2 and 4 hours with cranberries. Insulin, blood fats and blood pressure did not differ from the meal without cranberries. The Cranberry Institute and the Wisconsin Cranberry Board, two industry groups, supported it in part.
Daily cranberry powder improved blood vessel dilation by 1.1% in healthy men
In this double-blind trial, 45 healthy men took 9 g a day of freeze-dried whole cranberry powder for a month. That equals 100 g of fresh berries. Flow-mediated dilation, a test of how well the arteries widen, rose; blood pressure, blood fats and blood glucose did not change. The Cranberry Institute, a cranberry industry group, partly funded it.
Cranberry powder improved visual memory in healthy adults aged 50 to 80
This placebo-controlled trial in 60 people, which the authors call a feasibility study, ran for 12 weeks. The daily freeze-dried powder equaled 1 small cup of berries. Brain scans showed more blood flow in some regions, and LDL cholesterol fell. A Cranberry Institute grant funded it, and the paper says the institute was not involved in the design or analysis.
Daily cranberry juice did not change warfarin levels in 30 stable patients
In this double-blind trial, people on stable warfarin treatment drank 240 mL of cranberry juice a day or placebo for 2 weeks. The clotting measure INR differed between juice and placebo on one day only, which the authors think is unlikely to matter. Four people on juice and 4 on placebo had a mildly raised INR.
Cranberry raised the INR response to warfarin 30% in healthy men
In this open-label crossover trial, 12 healthy men took a single 25 mg dose of warfarin after 2 weeks of cranberry. INR measures how slowly blood clots. Cranberry did not change warfarin blood levels, and the authors call for careful monitoring when the two are used together.
Daily cranberry juice raised urinary oxalate and calcium oxalate saturation
In this crossover trial, 12 people without stones and 12 with calcium oxalate stones drank 1 L of cranberry juice a day for a week. They ate a controlled diet. Urinary oxalate rose from 26.4 to 29.2 mg a day, and calcium oxalate saturation in urine rose 18%. The risk of brushite stones fell, and the trial was small and short.
Diluted cranberry juice lowered urinary oxalate in 20 men without stones
In this crossover trial, South African male students without kidney stones drank 500 mL of cranberry juice diluted in water for 2 weeks. Phosphate excretion also fell, citrate rose, and calcium oxalate supersaturation was lower than with water alone. It points the other way from the study above, so the effect on stone risk is unclear.
In the lab, three cranberry A-type proanthocyanidins stopped E. coli sticking
This lab study tested compounds isolated from ripe cranberries against urinary E. coli sticking to cells. A related dimer was weakly active, while the single-unit epicatechin and the B-type dimer were inactive. This is the chemistry behind the cranberry and UTI idea, and it says nothing about people.
A sugar fraction from cranberry cut E. coli biofilm by over 50%
This lab study used purified, polyphenol-free cranberry oligosaccharides (sugar chains) at 1.25 mg/mL against a urinary E. coli strain. They did not kill the bacteria. Ocean Spray funded it in part, and two authors work there.
Who should be careful with cranberries
Most people can eat cranberries freely. Take a little care if one of these applies:
- Warfarin. The NHS says not to drink cranberry juice while taking warfarin, because it can increase the blood-thinning effect. Trials disagree on how big the risk is, so ask your clinic before you use juice or capsules.
- Sugar in sweetened juice and dried cranberries. Raw cranberries have 4.3 g of sugar per 100 g. USDA lists 11.9 g for bottled cranberry juice cocktail and 72.6 g for sweetened dried cranberries. In people with type 2 diabetes, sweetened dried cranberries raised blood sugar as high as white bread did. So check labels and keep portions small.
- Kidney stones. Two small trials disagree on whether cranberry juice raises or lowers urinary oxalate. If you have had calcium oxalate stones, ask your doctor before drinking it every day.
How to choose, store and eat cranberries
- Fresh or frozen: raw cranberries have 46 calories, 3.6 g of fiber and 14 mg of vitamin C per 100 g. They are very tart.
- Juice or capsules: the trial with the clearest result used one 240 mL serving of a cranberry juice beverage a day for 24 weeks. Nursing home capsules with 72 mg of proanthocyanidins did nothing.
- Sweetened dried cranberries: 40 g raised blood sugar to 9.6 mmol/L in people with type 2 diabetes, the same peak as white bread. A lower-sugar version peaked at 8.7.
Pick berries that are bright, shiny and firm, and drop one: a fresh berry bounces. They usually keep about 2 weeks in the fridge, or up to 4 weeks in the original package in the crisper drawer. A bag can go straight into the freezer for up to 12 months.
Sources
- Anticoagulant medicines: considerations. NHS.
- Ansell J, McDonough M, Zhao Y, Harmatz JS, Greenblatt DJ. The absence of an interaction between warfarin and cranberry juice: a randomized, double-blind trial. J Clin Pharmacol. 2009.
- Mohammed Abdul MI, Jiang X, Williams KM, et al. Pharmacodynamic interaction of warfarin with cranberry but not with garlic in healthy subjects. Br J Pharmacol. 2008.
- Gettman MT, Ogan K, Brinkley LJ, Adams-Huet B, Pak CY, Pearle MS. Effect of cranberry juice consumption on urinary stone risk factors. J Urol. 2005.
- McHarg T, Rodgers A, Charlton K. Influence of cranberry juice on the urinary risk factors for calcium oxalate kidney stone formation. BJU Int. 2003.
- Wilson T, Luebke JL, Morcomb EF, et al. Glycemic responses to sweetened dried and raw cranberries in humans with type 2 diabetes. J Food Sci. 2010.
- Maki KC, Kaspar KL, Khoo C, Derrig LH, Schild AL, Gupta K. Consumption of a cranberry juice beverage lowered the number of clinical urinary tract infection episodes in women with a recent history of urinary tract infection. Am J Clin Nutr. 2016.
- 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.
- Cranberry juice cocktail, bottled. USDA FoodData Central (SR Legacy).
- Cranberries, dried, sweetened. USDA FoodData Central (SR Legacy).
- Preserving cranberries. Penn State Extension.
History of cranberries
The American cranberry is a young crop. Researchers describe it as a North American fruit domesticated less than 200 years ago. The USDA began its first cranberry breeding program in 1929 to fight false-blossom disease. The first modern cultivars, from Rutgers University and the University of Wisconsin, arrived in the 2000s.
People knew the berry long before that. The Narragansett people of New England appear to have used cranberries in pemmican and as a dye. They may have introduced them to colonists in Massachusetts.
The name comes from the Middle Low German kraanbere. The missionary John Eliot used “cranberry” in English in 1647. Around 1694, German and Dutch colonists in New England saw a crane’s neck, head and bill in the berry’s flower.
In 1672, John Josselyn wrote in New England Rarities Discovered that cranberries were good against scurvy. He wrote that Native Americans and the English boiled them with sugar into a sauce for meat, especially roast mutton. Raw cranberries do hold vitamin C, though not a lot: 14 mg per 100 g, or 16% of the Daily Value.
Farming began with Henry Hall, a veteran of the American Revolution, who first cultivated cranberries around 1816 in Dennis on Cape Cod. By the 1820s he was shipping them to New York City and Boston, and some went on to Europe. By 1900, about 8,700 hectares in New England were planted.
Today the United States, Canada and Chile grow 97% of the world’s cranberries. Wisconsin alone grew 59% of the US harvest in 2021. The urinary tract idea has its own long history: the Cochrane review that now covers 50 trials was first published in 1998.
Regulators have been less convinced. In 2025, the European Food Safety Authority judged the evidence insufficient to support a claim for one cranberry powder. It noted that one trial showed a benefit and another did not consistently.
Sources
- Diaz-Garcia L, Covarrubias-Pazaran G, Johnson-Cicalese J, Vorsa N, Zalapa J. Genotyping-by-sequencing identifies historical breeding stages of the recently domesticated American cranberry. Front Plant Sci. 2020.
- Cranberry. Wikipedia.
- Preserving cranberries. Penn State Extension.
- Williams G, Stothart CI, Hahn D, Stephens JH, Craig JC, Hodson EM. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2023.
- Foo LY, Lu Y, Howell AB, Vorsa N. A-type proanthocyanidin trimers from cranberry that inhibit adherence of uropathogenic P-fimbriated Escherichia coli. J Nat Prod. 2000.
- EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA). Pacran, a powder obtained from cranberries, and defence against bacterial pathogens in the lower urinary tract: evaluation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006. EFSA J. 2025.
Frequently asked questions about cranberries
Are cranberries good for you?
For most people, yes, with the strongest evidence in one area. Raw cranberries have 46 calories, 3.6 g of fiber and 14 mg of vitamin C per 100 g, and only 4.3 g of sugar. A Cochrane review of 50 trials found a risk ratio of 0.70 for urinary tract infections, though results varied. The heart and blood sugar results here are small and mixed, and sweetened juice and dried cranberries add a lot of sugar.
Do cranberries prevent urinary tract infections?
Sometimes: the Cochrane review found lower risk in women with recurrent infections (0.74), in children (0.46) and after medical procedures (0.47). It found little or no benefit in nursing home residents (0.93) and pregnant women (1.06). Juice failed in 319 college women (a second UTI in 20.0% on cranberry against 14.0% on placebo). Capsules failed in nursing homes (29.1% against 29.0%), and a daily antibiotic beat cranberry capsules, with 1.8 UTIs a year against 4.0.
Does cranberry juice cure a UTI?
No study shows that. A Cochrane review found no randomized trials of cranberry as a treatment for an existing UTI, so there is no good-quality evidence that it works. If you have burning, urgency, fever or back pain, see a doctor instead of waiting on juice.
How much cranberry juice should you drink a day?
No study sets an ideal amount: the 24-week trial with fewer UTIs (39 against 67) used one 240 mL serving a day. The H. pylori trial used two servings a day of a high-proanthocyanidin juice. A week of 1 L a day raised urinary oxalate in a small stone trial. Cranberry juice cocktail has 11.9 g of sugar per 100 g, so unsweetened juice is the lower-sugar choice.
Are dried cranberries healthy?
They are a sugary snack, not a swap for the raw fruit. USDA lists 72.6 g of sugar per 100 g for sweetened dried cranberries, against 4.3 g in raw ones. In 13 people with type 2 diabetes, 40 g of sweetened dried cranberries peaked blood sugar at 9.6 mmol/L, the same as white bread. A lower-sugar version peaked at 8.7; keep portions small and check the label.
Can you eat cranberries raw?
Yes, but they are firm and very sour. Raw cranberries have 46 calories and 3.6 g of fiber per 100 g. Most people cook them with a little sweetener or mix them into other foods, which is why about 95% of the crop is processed.
Can you take cranberry with warfarin?
Ask your clinic first. The NHS says not to drink cranberry juice while taking warfarin, because it can increase the blood-thinning effect. The trials disagree: after 2 weeks of cranberry, the INR response to one warfarin dose rose 30% in 12 healthy men. But 240 mL of juice a day did not change warfarin levels in 30 patients on stable treatment.
Is cranberry juice good for kidney stones?
The evidence is small and mixed. In a week-long trial, 1 L of juice a day raised urinary oxalate and increased calcium oxalate saturation in urine by 18%. But 500 mL diluted in water for 2 weeks lowered urinary oxalate in 20 men. If you have had calcium oxalate stones, ask your doctor before making it a daily habit.