Cranberry sauce: the UTI trials used juice and capsules, and warfarin is the open question

A network meta-analysis of 50 randomized trials with 10,495 people found cranberry products cut urinary tract infections by about 28% against placebo (RR 0.72, 0.60 to 0.87). Those products were juices and capsules. In 16 trials in 1426 children, cranberry in various forms, none of them sauce, roughly halved recurrence against placebo (RR 0.48, 95% CI 0.28 to 0.80) and showed no clear difference from preventive antibiotics. We found no trial of the sauce itself, sweetened as it is. Canned sweetened sauce carries about 40 g of carbohydrate and 1.1 g of fiber per 3.5 oz (100 g), and the US survey counts a slice as 50 g and an unspecified serving as 70 g. The USDA factor for canned fruit in general, taken from an old table and never measured on the sauce, puts vitamin C retention at 50%.

The numbers, per 3.5 oz (100 g)

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• USDA lists canned sweetened cranberry sauce at about 40 g carbohydrate and 1.1 g fiber per 3.5 oz (100 g). — USDA SR Legacy record, canned sweetened cranberry sauce Evidence E source
  Per 100 g: carbohydrate 40.4 g; fiber 1.1 g; vitamin E 0.93 mg

What a real portion looks like

• The US dietary survey database counts a slice of cranberry sauce as 50 g, an unspecified serving as 70 g and a cup as 280 g. — FNDDS portion weights, US Evidence E source
  1 slice = 50 g; quantity not specified = 70 g; 1 cup = 280 g

What cooking and storage change

• By the USDA retention table for canned fruits, canning keeps about 50% of vitamin C and folate and 80% of thiamin. — USDA retention factors, group Fruits and Fruit Juices, method canned Evidence E source
  Retained: vitamin C 50%; folate 50%; thiamin 80%; potassium 90%; iron 100%

What it does to your health

• A network meta-analysis of 50 randomized trials with 10,495 people found cranberry products cut urinary tract infection incidence by about 28% versus placebo. — 50 RCTs, 10,495 subjects (n = 10495) Evidence A source
  Cranberry RR 0.72 (0.60 to 0.87) vs placebo; adverse events no different from placebo

Safety, limits and interactions

• A case report describes a man on warfarin whose INR rose to 4.8 after eating about 4 oz (113 g) of store-bought cranberry sauce daily for seven days. — one 75-year-old man with atrial fibrillation on warfarin (n = 1) Evidence D source
  INR 4.8 from a stable 2-3; returned to 2.2 seven days after stopping the sauce
• In a double-blind randomized trial in 30 patients on stable warfarin, 240 mL of cranberry juice daily for 2 weeks did not change warfarin levels and raised INR only on one day. — 30 patients on stable warfarin (INR 1.7-3.3); 2 weeks (n = 30) Evidence B source
  No difference in R- and S-warfarin; mean INR differed only on day 12 (P < .02)
• In a randomized crossover trial in 12 healthy men, two weeks of cranberry before a single warfarin dose raised the INR area under the curve by 30%. — 12 healthy men of known CYP2C9 and VKORC1 genotype; single 25 mg warfarin dose (n = 12) Evidence B source
  INR-time AUC +30% with cranberry; no change in warfarin pharmacokinetics
• In a double-blind crossover trial of 7 men on warfarin, 250 mL of cranberry juice daily for 7 days did not change INR. — 7 men with atrial fibrillation on stable warfarin; 7-day periods (n = 7) Evidence B source
  INR 2.23 on cranberry vs 2.16 on placebo at day 7; no significant difference
• A systematic review of 149 articles lists cranberry among foods and herbs that may raise bleeding risk with warfarin. — 149 articles on 78 herbs, foods or supplements (n = 149 articles) Evidence C source
  Cranberry named with increased bleeding risk; mostly case-level evidence

Who this works differently for

• A case report describes an 85-year-old woman on warfarin whose INR rose two- to three-fold after two separate servings of cranberry sauce. — one 85-year-old woman on chronic warfarin for atrial fibrillation (n = 1) Evidence D source
  INR elevations of two- to three-fold on two occasions
• A meta-analysis of 16 randomized trials in 1426 children found cranberry roughly halved UTI recurrence versus placebo and showed no clear difference from antibiotic prophylaxis. — 16 RCTs, 1426 children (n = 1426) Evidence A source
  Vs placebo RR 0.48 (95% CI 0.28-0.80); vs antibiotics RR 0.92 (95% CI 0.56-1.50)

What is still unknown

• A review of warfarin case reports notes that most controlled studies found no significant cranberry interaction, while case reports suggest one. No trial has tested cranberry sauce itself. — published pharmacokinetic and pharmacodynamic studies and case reports Evidence C source
  Conflicting: trials mostly null, case reports positive

The bottom line

If you take warfarin, the sauce itself has a record. A 75-year-old man with atrial fibrillation ate about 4 oz (113 g) of cranberry sauce a day for seven days after Thanksgiving, and at his next clinic visit his INR was 4.8. An 85-year-old woman on long-term warfarin had her INR rise two- to three-fold after two separate helpings. These are two single cases. The controlled trials mostly used juice and mostly found little. In 30 patients on stable warfarin, 240 mL of juice a day for 2 weeks left warfarin blood levels unchanged and shifted INR on only one day. In 7 men, 8.5 fl oz (250 mL) a day for 7 days did not change INR. In 12 healthy men given a single warfarin dose, two weeks of a cranberry preparation raised the INR area under the curve by 30%. Whether this is a real interaction is still open. A review of the published studies notes that most controlled pharmacokinetic and pharmacodynamic studies found no significant interaction, while several case reports suggest cranberry products raise INR. A systematic review of 149 articles lists cranberry among foods and herbs that may raise bleeding risk with warfarin, mostly on case-level evidence. How much sauce is safe alongside warfarin is not known. A daily holiday helping for a week is the pattern in the case report, and that is worth mentioning to whoever checks your INR.

Sources

1. cbs-r6-01 · food composition dataset
   Cranberry sauce, canned, sweetened (FDC 173961, SR Legacy, Fruits and Fruit Juices): carbohydrate 40.4 g per 100 g; fiber 1.1 g; vitamin E 0.93 mg
   USDA FoodData Central SR Legacy, FDC 173961 Cranberry sauce, canned, sweetened · checked 2026-09-29
2. cbs-r6-02 · portion dataset
   Cranberry sauce | FNDDS 63207110 | fdc_id 2709280 | 1 slice 50 g | 1 cup 280 g | Quantity not specified 70 g
   USDA FNDDS, Cranberry sauce, food code 63207110 (fdc_id 2709280) · checked 2026-09-29
3. cbs-r6-03 · retention dataset
   USDA-RETN-R6:154 FRUITS,CANNED | Fruits and Fruit Juices (9) | vitamin_c_mg 50% | folate_total_ug 50% | thiamin_mg 80% | potassium_mg 90% | iron_mg 100%
   USDA Table of Nutrient Retention Factors, Release 6 (2007), Retn_Code 154 FRUITS,CANNED · checked 2026-09-29
4. cbs-r6-10 · network meta-analysis
   50 RCTs comprising 10,495 subjects and investigating 14 interventions, were included. ... In the whole group, D-mannose (risk ratio [RR] 0.34, 0.21 to 0.56), vaccine (RR 0.65, 0.52 to 0.82), probiotics (RR 0.69, 0.50 to 0.94), cranberry (RR 0.72, 0.60 to 0.87), and triple therapy (cranberry plus probiotics plus vitamin A) (RR 0.27, 0.09 to 0.87), exhibited a significant reduction in UTI incidence compared to the placebo.
   Infection, 2025 · checked 2026-09-29
5. cbs-r6-04 · case report
   During a clinic visit one week after Thanksgiving, the patient's INR was 4.8. ... The patient reported consuming approximately 113 g of cranberry sauce for seven consecutive days before the clinic visit.
   Am J Health Syst Pharm, 2008 · checked 2026-09-29
6. cbs-r6-06 · randomized controlled trial
   Thirty patients on stable warfarin anticoagulation (international normalized ratio [INR], 1.7-3.3) were randomized to receive 240 mL of CJ or 240 mL of placebo beverage, matched for color and taste, once daily for 2 weeks. ... Mean INR differed significantly (P<.02) only on treatment day 12; at all other time points, the groups did not differ.
   J Clin Pharmacol, 2009 · checked 2026-09-29
7. cbs-r6-07 · randomized crossover trial
   Cranberry significantly increased the area under the INR-time curve by 30% when administered with warfarin compared with treatment with warfarin alone.
   Br J Pharmacol, 2008 · checked 2026-09-29
8. cbs-r6-08 · randomized crossover trial
   Seven subjects with atrial fibrillation on a stable dose of warfarin for 3 months were randomized to consume 250 mL of cranberry juice for 7 days, then placebo for 7 days, or vice versa. ... For all test points, the INR did not change significantly from baseline.
   J Am Diet Assoc, 2006 · checked 2026-09-29
9. cbs-r6-09 · systematic review
   While most food, herbs and supplements can be safely taken in moderation, healthcare professionals should be aware of the increased risk of bleeding when taking several food and herbs. These include Chinese wolfberry, chamomile tea, cannabis, cranberry, chitosan, green tea, Ginkgo biloba, ginger, spinach, St. John's Wort, sushi and smoking tobacco.
   Br J Clin Pharmacol, 2021 · checked 2026-09-29
10. cbs-r6-05 · case report
    An 85-year-old woman on chronic warfarin therapy for atrial fibrillation experienced INR elevations of two- to three-fold after two separate ingestions of cranberry sauce.
    Consult Pharm, 2012 · checked 2026-09-29
11. cbs-r6-11 · meta-analysis of RCTs
    Sixteen trials evaluating 1426 participants were included. Cranberry was as effective as antibiotic prophylaxis (RR: 0.92; 95% CI: 0.56-1.50) but better than placebo/no therapy (RR: 0.48; 95% CI: 0.28-0.80) in reducing UTI recurrence.
    Eur J Pediatr, 2021 · checked 2026-09-29
12. cbs-r6-12 · literature review
    Although the majority of the pharmacokinetic and pharmacodynamic studies did not find a significant interaction between cranberry and warfarin, several case reports indicate that cranberry products may increase INR values in patients on warfarin.
    Consult Pharm, 2012 · checked 2026-09-29