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Cranberry

Medically reviewed on June 7, 2018

What is Cranberry?

The cranberry plant is native to eastern North America. A number of related cranberries are found in areas ranging from damp bogs to mountain forests. These plants grow from Alaska to Tennessee as small, trailing evergreen shrubs. Their flowers vary from pink to purple and bloom from May to August depending on the species.

Scientific Name(s)

Vaccinium macrocarpon

Common Name(s)

Cranberry, American cranberry, arandano Americano, arandano rtepador, grosse moosbeere, kranbeere, tsuru-kokemomo, vaccinium.

What is it used for?

Traditional/Ethnobotanical uses

The cranberry was primarily used as a traditional medicine for the treatment of bladder and kidney ailments among American Indians. The berries were also used as a fabric and food dye, and as a poultice to treat wounds and blood poisoning. Sailors used the berries to prevent scurvy. Despite a general lack of scientific evidence that cranberries or their juice are effective urinary acidifiers, interest persists among the public in their medicinal use. Cranberries are used in Eastern European cultures, due to folklore, to reduce fever and to treat cancers.

General uses

Some evidence exists for the use of cranberry in preventing, but not treating, urinary tract infections. Other possible uses for cranberry with limited evidence include reduction of the risk of heart disease and cancer treatment.

What is the recommended dosage?

Cranberry juice, juice concentrate, and dried extract have been studied in urinary tract infections; however, consistent dose regimens have not been used. Doses of juice cocktail (25% pure cranberry juice) have ranged from 120 to 1,000 mL/day in divided doses. Concentrated cranberry extract in the form of tablets and capsules is available and 600 to more than 1,200 mg/day in divided doses have been used in studies in urinary tract infections.

Contraindications

Those prone to kidney stones should contact their health care provider before taking a cranberry product.

Pregnancy/Lactation

Information is limited; however, when ingested at normal food consumption amounts, cranberry is considered relatively safe in pregnancy. Safety during lactation is unknown.

Interactions

An interaction between cranberry and warfarin has been suggested based on case reports; however, evidence for a causal relationship is lacking from clinical trials.

Side Effects

The berries and juice have few ill effects associated with their consumption. Large daily doses may produce GI symptoms, such as diarrhea. Concentrated cranberry tablets may predispose patients to kidney stones.

Toxicology

Information is lacking.

References

1. Cranberry. Review of Natural Products. Facts & Comparisons [database online]. St. Louis, MO: Wolters Kluwer Health Inc; August 2012.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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