Cranberries and Your Health

Medically Reviewed by Kathleen M. Zelman, RD, LD, MPH on May 02, 2023
3 min read

The red berries of the cranberry shrub are common in foods such as juice and muffins. Traditionally, cranberries have been used for urinary conditions and other ailments.

A number of studies, many sponsored by juice manufacturer Ocean Spray, show that cranberry juice helps prevent urinary tract infections (UTIs) in people who repeatedly have them. Some studies of cranberry supplements have had similar results. Cranberries might stop bacteria from sticking to the sides of the urinary tract. 

In 2020, the FDA decided to permit makers of cranberry dietary supplements to say that there is "limited" evidence that these may help prevent recurrent urinary tract infections. Cranberry juice may also be labeled to say that there is "limited and inconsistent" for the same claim.

Studies have not shown that cranberries are effective treatments for UTIs once you have an infection.

Cranberries could help in other ways. Some research suggests that they might help prevent H. pylori infections in the stomach that lead to ulcers. They also might slow the buildup of dental plaque.

Cranberry is full of antioxidants, which are thought to protect cells from damage. Some lab studies show that cranberries might have an anticancer effects on cells. It isn't known if it might help people with cancer.

People take cranberry for other conditions. They range from arthritis to eczema to gout. There is no good evidence to support these uses, however.

There is no standard dose of cranberry. Some studies have used 1/2 ounce of cranberry juice twice a day to help prevent recurrent UTIs. Other studies have used between 600-800 milligrams daily of cranberry supplement capsules.

Cranberries are a common food. They're sold fresh, frozen, dried, and sweetened. They're also in products like juice, jelly, sauce, baked goods, and tea.

  • Side effects. Cranberries, cranberry juice, and cranberry extracts are safe. Excessive amounts could cause upset stomach or diarrhea. Pregnant women might suffer these side effects at lower doses.
  • Risks. If you think you have a urinary tract infection, don't rely on cranberries. There's no good evidence that it will help. Instead, see a doctor. If you have health conditions like aspirin allergy or kidney stones, check with a doctor before using cranberry for a health condition. Sweetened cranberry drinks can be high in calories and high-fructose corn syrup, and thus may be inadvisable for people with diabetes or weight problems.
  • Interactions. If you take any drugs regularly, talk to your doctor before you start using cranberry supplements. They could interact with medicines like blood thinners, some antibiotics, aspirin, statins, antacids, proton pump inhibitors, and drugs that affect the liver.

While cranberry juice is generally safe, children or women who are pregnant or breastfeeding should not take cranberry for medical purposes unless a doctor recommends it.