Cranberry (Vaccinium macrocarpon)
Photo: Keith Weller, USDA-ARS · Public domain
- Urinary
- 2 conditions
- Licensed photo
Overview
Cranberry (Vaccinium macrocarpon) is a small, low-lying evergreen shrub with dark green leaves, pink flowers, and bright red berries. Cranberries contain proanthocyanidins, which NCCIH says are thought to keep bacteria from sticking to the bladder wall. Cranberry juice or extracts are widely used to try to prevent urinary tract infections (UTIs); NCCIH says they may lower the risk of repeat UTIs in some women but are not recommended as a treatment for an existing UTI. MSK notes that the fruit and juice are rich in vitamin C.
Traditional uses & properties
Nutritive: Contains vitamin C. Urinary Tract Support: NCCIH says cranberry may lower the risk of repeat UTIs in women, although findings are inconsistent.
Safety & precautions
Kidney Disease: Seek professional advice if you have existing kidney issues, as cranberry’s acidity may be problematic in certain cases.
Educational reference only - not medical advice. Herbs can interact with medications. Consult a qualified healthcare provider before use. Full disclaimer.
Drug interactions
The most studied question is warfarin, and the evidence points in different directions. [1, 2]
- Warfarin
- NCCIH calls the evidence conflicting. MSK notes case reports of bleeding, including two deaths in older adults, and says cranberry use by people on warfarin should be watched by a health professional, if not avoided. A 2021 systematic review lists cranberry among foods and herbs linked to higher bleeding risk with warfarin. [1, 2, 3]
- Tacrolimus
- MSK describes a kidney transplant patient whose tacrolimus level fell too low while taking cranberry extract and recovered after stopping it. [2]
- Cyclosporine
- A randomized trial cited by MSK found cranberry juice had no clinically meaningful effect on cyclosporine. [2]
- Acid reducing medicines (PPIs and H2 blockers)
- LiverTox notes that cranberry juice or extract may lower blood levels and effects of these drugs. [4]
- Medicines broken down by gut or liver enzymes
- MSK reports that cranberry inhibits CYP3A activity in the gut and affects UGT enzymes in the laboratory. A CYP2C9 effect seen in the laboratory did not appear in people. [2]
How to read this section: each entry is HerbMate's summary of what the cited sources report. Words such as "may", "theoretical" or "in laboratory or animal studies" mean the effect has not been confirmed in people, and "case report" means it was seen in one or a few patients. A medicine that is not listed here has not been shown to be safe with this herb. The numbers in brackets link to the sources at the foot of the page.
Habitat
Native to eastern North America and parts of northern Asia, cranberry thrives in acidic, boggy soils. Commercial production is large-scale in the northeastern U.S. and Canada. The berries are harvested in late fall.
Sources
The interaction notes and the statements on this page that name a source were written by HerbMate from these references, which were last checked in October 2026. They are summaries, not medical advice; ask a pharmacist about your own medicines.
Traditionally used for
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Frequently asked questions
What is Cranberry (Vaccinium macrocarpon) traditionally used for?
Traditional sources describe Cranberry (Vaccinium macrocarpon) as follows: Nutritive: Contains vitamin C. Urinary Tract Support: NCCIH says cranberry may lower the risk of repeat UTIs in women, although findings are inconsistent.
What safety cautions apply to Cranberry (Vaccinium macrocarpon)?
Kidney Disease: Seek professional advice if you have existing kidney issues, as cranberry’s acidity may be problematic in certain cases.
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