Cranberry 

This fact sheet provides basic information about cranberry—common names, 

uses, potential side effects, and resources for more information. Cranberries are 

the fruit of a native plant of North America. These red berries are used in foods 

and in herbal products. 

Common Names—cranberry, American cranberry, bog cranberry 

Latin Name—Vaccinium macrocarpon 

What It Is Used For 

•	 Historically, cranberry fruits and leaves were used for a variety of problems, 

such as wounds, urinary disorders, diarrhea, diabetes, stomach ailments, 

and liver problems. 

•	 Recently, cranberry products have been used in the hope of preventing or 

treating urinary tract infections or Helicobacter pylori infections that can lead 

to stomach ulcers, or to prevent dental plaque. Cranberry has also been 

reported to have antioxidant and anticancer activity. 

How It Is Used 

The berries are used to produce beverages and many other food products, as well 

as dietary supplements in the form of extracts, teas, and capsules or tablets. 

What the Science Says 

•	 Some studies testing cranberry products for their ability to prevent urinary 

tract infections have shown promise. These studies have generally been 

small in size, and some were not randomized or controlled; therefore, the 

results are not conclusive. 

•	 Cranberry products have not been adequately tested to see if they can be 

used to help treat an existing urinary tract infection. 

•	 Research shows that components found in cranberry may prevent bacteria, 

such as E. coli, from clinging to the cells along the walls of the urinary tract 

and causing infection. However, the mechanism of action of cranberry is not 

fully understood. 

•	 NCCAM, the National Institute of Diabetes and Digestive and Kidney 

Diseases, and the National Institute for Dental and Craniofacial Research are 

funding studies to understand whether and how cranberry might work to: 

ο Prevent urinary tract infection 

ο Prevent the formation of dental plaque. 
 

Side Effects and Cautions 

•	 Eating cranberry products in food appears to be safe, but drinking excessive amounts of 

juice could cause gastrointestinal upset or diarrhea. 

•	 People who think they have a urinary tract infection should see a health care provider for 

proper diagnosis and treatment. Cranberry products should not be used to treat infection. 

•	 Tell your health care providers about any complementary and alternative practices you 

use. Give them a full picture of what you do to manage your health. This will help ensure 

coordinated and safe care. 

Sources 

Cranberry (Vaccinium macrocarpon) Aiton. In: Coates P, Blackman M, Cragg G, et al., eds. Encyclopedia of Dietary 

Supplements. New York, NY: Marcel Dekker; 2005:143-149. 

Cranberry. Natural Medicines Comprehensive Database Web site. Accessed at http://www.naturaldatabase.com on 

July 2, 2007. 

Cranberry (Vaccinium macrocarpon). Natural Standard Database Web site. Accessed at http://www.naturalstandard.com

on June 28, 2007. 

For More Information 

Visit the NCCAM Web site at nccam.nih.gov and view: 

•	 What’s in the Bottle? An Introduction to Dietary Supplements at nccam.nih.gov/health/bottle/ 

•	 Herbal Supplements: Consider Safety, Too at nccam.nih.gov/health/supplement-safety/

NCCAM Clearinghouse 

Toll-free in the U.S.: 1-888-644-6226 

TTY (for deaf and hard-of-hearing callers): 1-866-464-3615 

E-mail: info@nccam.nih.gov

CAM on PubMed 

Web site: nccam.nih.gov/camonpubmed/

NIH Office of Dietary Supplements 

Web site: www.ods.od.nih.gov

NIH National Library of Medicine’s MedlinePlus 

Cranberry Listing: www.nlm.nih.gov/medlineplus/druginfo/natural/patient-cranberry.html

This publication is not copyrighted and is in the public domain. Duplication is encouraged. 

NCCAM has provided this material for your information. It is not intended to substitute 

for the medical expertise and advice of your primary health care provider. We encourage 

you to discuss any decisions about treatment or care with your health care provider. The 

mention of any product, service, or therapy is not an endorsement by NCCAM. 

National Institutes of Health 

♦♦♦

U.S. Department of Health and Human Services 

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Created September 2005 

Updated March 2008 

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