cranberry
Useful mainly for women with recurrent urinary tract infections seeking prevention.
Quick decision guide
May help most
women with recurrent urinary tract infections seeking prevention
Common dosing range
≥36 mg A-type proanthocyanidins/day (e.g. 300–500 mg extract twice daily)
When to expect effects
Weeks (prevention, not acute treatment)
Watch out for
does not treat an active UTI and must not delay antibiotics
What is it
Cranberry (Vaccinium macrocarpon) is a tart North American berry whose juice, dried fruit, and concentrated extracts are widely used for urinary tract health. It is one of the most-studied dietary supplements for prevention of recurrent urinary tract infections (UTIs).
Is it worth it for you?
Use this as a quick fit check, not a diagnosis.
Worth considering if…
Probably skip if…
Evidence at a glance
| Goal | Effect | Best fit | Time |
|---|---|---|---|
recurrent UTI prevention in women Good Evidence | Modest reduction in recurrence | women with recurrent uncomplicated UTIs | Weeks |
UTI prevention in older adults and post-procedure patients Limited Evidence | Small, inconsistent | older adults or patients after urinary procedures | Weeks |
cardiovascular markers Limited Evidence | Small | adults seeking vascular marker support | Weeks |
oral health Limited Evidence | Unclear | general adults | Unclear |
treatment of established UTIs Mixed Evidence | No reliable effect | not appropriate as treatment | Not applicable |
recurrent UTI prevention in women
- Effect
- Modest reduction in recurrence
- Best fit
- women with recurrent uncomplicated UTIs
- Time
- Weeks
UTI prevention in older adults and post-procedure patients
- Effect
- Small, inconsistent
- Best fit
- older adults or patients after urinary procedures
- Time
- Weeks
cardiovascular markers
- Effect
- Small
- Best fit
- adults seeking vascular marker support
- Time
- Weeks
oral health
- Effect
- Unclear
- Best fit
- general adults
- Time
- Unclear
treatment of established UTIs
- Effect
- No reliable effect
- Best fit
- not appropriate as treatment
- Time
- Not applicable
Evidence for 5 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
recurrent UTI prevention in women
Supplement benefitMeta-analyses indicate cranberry products reduce the risk of recurrent UTIs in otherwise healthy women, via A-type proanthocyanidins that block E. coli adhesion to the bladder wall. The effect is modest and depends on adequate proanthocyanidin dose; low-concentration juices show little benefit.
Bottom line: A reasonable non-antibiotic option to modestly cut recurrent UTIs in women.
UTI prevention in older adults and post-procedure patients
Supplement benefitEvidence in elderly, catheterized, or post-procedure populations is weaker and inconsistent, with several trials showing no significant reduction in infections. Benefit in these groups is uncertain.
Bottom line: Less convincing outside otherwise-healthy women; benefit is uncertain.
Evidence is mixed
Trials in elderly and catheterized patients are mixed, with several null results.
cardiovascular markers
Biomarker supportCranberry polyphenols have produced small improvements in endothelial function, blood pressure, and lipid markers in some trials. These are biomarker changes; clinical cardiovascular benefit is not established.
Bottom line: May nudge vascular markers, but no proven heart-disease benefit.
oral health
Mechanism onlyCranberry proanthocyanidins reduce bacterial adhesion and biofilm formation relevant to dental plaque in laboratory and early studies. Controlled clinical evidence for cavities or gum disease outcomes is limited.
Bottom line: Anti-adhesion effects are plausible for oral bacteria, but clinical benefit is unproven.
treatment of established UTIs
Supplement benefitCranberry works by preventing bacterial adhesion, not by killing established bacteria, and does not treat an active infection. Using it in place of antibiotics risks worsening infection.
Bottom line: Not a treatment for an active UTI; do not substitute it for antibiotics.
How it works
How to take it
What to track
4 commercial forms
Compare the main delivery options and what they’re best suited for.
Standardized cranberry extract capsules
Provides consistent PAC dose without the sugar or volume of juice. Most common in modern UTI prevention products.
Standardized to A-type proanthocyanidin content (often 36 mg+ per day)
Unsweetened cranberry juice
Traditional form. Pure unsweetened juice is more concentrated than 'cocktail' versions.
Lower PAC concentration; requires larger volumes
Cranberry juice cocktail
Provides limited PACs unless consumed in large amounts. Often high in added sugar.
Diluted and sweetened; low PAC per serving
Dried cranberries
Provides whole-food cranberry with variable PAC content. Often contains added sugar.
Concentrated in fiber, but often sweetened
Safety
Know the common side effects, key cautions, and who should avoid it.
Common side effects
Who should avoid it
- history of calcium oxalate kidney stones (use caution)
- anyone using it to delay antibiotic treatment of an active UTI
Pregnancy & breastfeeding
Generally well tolerated in pregnancy; discuss high-dose supplements with your obstetric provider.
Interactions
case reports of enhanced anticoagulation; monitor INR with regular use
may increase oxalate excretion
Documented interactions
Evidence-graded pair pages with sources, dosing notes, and timing guidance — a complement to the narrative section above.
Warnings (2)
+ warfarin
highCranberry contains flavonoids and polyphenols that may slow CYP2C9, the liver enzyme that clears the more potent S-enantiomer of warfarin. Multiple human case reports describe a rising INR and serious bleeding in patients who took up cranberry juice or supplements while stably anticoagulated, and the effect appears to depend on how much cranberry is consumed: randomized trials using a modest daily amount have not consistently reproduced it.
+ tacrolimus
moderateThe only human report on cranberry and tacrolimus showed tacrolimus levels falling sharply, not rising; lab studies predict the opposite, so the true direction is genuinely unpredictable. Because tacrolimus has a very narrow therapeutic window, any change in cranberry intake deserves a trough check.
Food sources
| Food | Amount | %DV |
|---|---|---|
| Fresh cranberries | 1 cup (~100g) | — |
| Cranberry juice (unsweetened, pure) | 240-300 mL | — |
| Cranberry juice cocktail | Diluted; large volumes needed for clinical PAC dose | — |
| Dried cranberries (sweetened) | Variable; check label | — |
Fresh cranberries
- Amount
- 1 cup (~100g)
- %DV
- —
Cranberry juice (unsweetened, pure)
- Amount
- 240-300 mL
- %DV
- —
Cranberry juice cocktail
- Amount
- Diluted; large volumes needed for clinical PAC dose
- %DV
- —
Dried cranberries (sweetened)
- Amount
- Variable; check label
- %DV
- —
Choosing a product
What to look for on the label — and what to be skeptical of.
Look for…
Be skeptical of…
Frequently asked questions
Can cranberry treat a UTI I already have?⌄
No. Cranberry is for prevention, not treatment. Established UTIs require antibiotic therapy from a clinician. Drinking cranberry juice will not cure an active infection.
Is cranberry juice as good as cranberry extract?⌄
Pure unsweetened cranberry juice in adequate volume can provide useful PACs, but sweetened cranberry cocktail provides much less. Concentrated extract capsules deliver standardized PAC doses without the sugar load.
How much cranberry do I need for UTI prevention?⌄
Clinical trials typically use products providing at least 36 mg of A-type proanthocyanidins per day. Check supplement labels for PAC content.
Is cranberry safe with warfarin?⌄
Case reports suggest possible interaction; clinical trials show mixed results. If you take warfarin and want to use cranberry regularly, discuss with your prescriber and have INR monitored.
Can men benefit from cranberry?⌄
Most UTI evidence is in women, but men with recurrent UTIs may also benefit. UTI is far less common in men, and recurrent UTIs in men warrant medical evaluation.
References by claim
Track cranberry with Pilora
Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.
Coming to App StoreDisclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.