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Laura Shane-McWhorter

, PharmD, University of Utah College of Pharmacy

Last full review/revision Jul 2020| Content last modified Jul 2020

Cranberries are fruit that can be consumed whole or made into food products such as jellies and juices.

(See also Overview of Dietary Supplements.)

Medicinal claims

People most often take cranberries to help prevent and relieve the symptoms of urinary tract infections (UTIs). The effectiveness of cranberries in preventing urinary tract infections has been documented in some studies, but not in others. However, recent analyses showed 26 to 33% decreases in UTIs. Natural unprocessed cranberry juice contains anthocyanidins, which prevent Escherichia coli (the bacteria that usually cause urinary tract infections) from attaching to the urinary tract wall.

Some people take cranberry juice to reduce fever and treat certain cancers. However, there is no scientific proof that it is effective for these uses.

Possible side effects

No side effects are known. However, because most cranberry juice is highly sweetened to offset its tart taste, people with diabetes should not consume cranberry juice unless it is artificially sweetened. People who have kidney stones should consult their doctor before taking cranberry products.

Possible drug interactions

Cranberry products may increase the effects of drugs that prevent blood clots (such as the anticoagulant warfarin), causing severe bleeding.

More Information about Cranberry

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  • National Institutes of Health (NIH), National Center for Complementary and Integrative Health: General information on the use of cranberry as a dietary supplement

Drugs Mentioned In This Article

Generic Name Select Brand Names
warfarin COUMADIN

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