(See also Overview of Medicinal Herbs and Nutraceuticals.)
Cranberries are fruit that can be consumed whole or made into food products such as jellies and juices.
People most often take cranberries to help prevent and relieve the symptoms of urinary tract infections. The effectiveness of cranberries in preventing urinary tract infections has been documented. 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.