Latin Name – Vaccinium macrocarpon
Cranberries are the fruit of a native plant of North America. These bright red berries are used to produce popular beverages such as cranberry juice and many other food products, as well as dietary supplements in the form of extracts, teas, capsules and tablets.
Historically, cranberry fruits and leaves were used as an herbal remedy 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 potential antioxidant activity.
Some studies testing cranberry products for their ability to help 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 help 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:
- Prevent urinary tract infection
- Prevent the formation of dental plaque.
Side Effects and Cautions Summary
- Drinking excessive amounts of cranberry 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 to help ensure coordinated and safe care. Complementary or alternative therapy should not be used in place of conventional medical care or to delay seeking that care.
- 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 on July 2, 2007.
- Cranberry (Vaccinium macrocarpon). Natural Standard Database Web site. Accessed on June 28, 2007.
For More Information
The National Center for Complementary and Alternative Medicine (NCCAM) Clearinghouse
The NCCAM Clearinghouse provides information on CAM and NCCAM, including publications and searches of Federal databases of scientific and medical literature. The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.
NIH Office of Dietary Supplements
Web site: ods.od.nih.gov
NIH National Library of Medicine’s MedlinePlus
Cranberry Listing: www.nlm.nih.gov/medlineplus/druginfo/natural/patient-cranberry.html
Source: National Center for Complementary and Alternative Medicine, Cranberry fact sheet, Created September 2005, Updated March 2008