Side Effects of Cranberry Tablets

Cranberry tablets are commonly taken for the purpose of treating or preventing urinary tract infections.
Image Credit: Ana Lukascuk/Moment/GettyImages

Cranberry tablets are commonly taken for the purpose of treating or preventing urinary tract infections (UTIs), which occur in at least 60 percent of women at some point in their lives. Before getting started on a supplement regimen, you must know the potential cranberry supplements side effects.


Cranberry Pills Side Effects

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Cranberry tablets are often used for the prevention of UTIs, which are widespread among women. Despite the many health benefits of cranberries, there are a few cranberry supplement side effects.

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An article in NIH: National Center for Complementary and Integrative Health, states that large amounts of cranberries or a high cranberry pills dosage can result in stomach upset and may increase your risk of developing kidney stones.

Furthermore, cranberry tablets can interact poorly with certain drugs. For instance, large doses of cranberry can alter the effectiveness of warfarin, a blood-thinner. As a general matter, it's important to consult your doctor before taking cranberry tablets, as you run the risk of inducing negative reactions with medicines.

A February 2012 review by Clinics states that side effects commonly reported from those consuming cranberry juice on a regular basis included headaches, frequent bowel movements, mild nausea, reflux, elevation in blood glucose levels and a skin reaction. There have also been some reported cases of thrombocytopenia, or deficiency of platelets in the blood.


Read more: How the Right Amount of Dried Cranberries Can Offer Great Health Benefits?

Cranberry and UTIs

There are several studies and reviews on the efficacy of cranberry juice or cranberry tablets in treating UTIs, many of which have conflicting results. A November 2016 study in JAMA, studied 147 women living in nursing homes who took two cranberry capsules daily. While the tablets decreased bacteria levels in the first six months of the study, they didn't decrease UTI frequency over the year.


A July 2012 review in Archives of Internal Medicine, which reviewed 13 clinical trials, found that cranberries may reduce the risk of UTIs in particular groups such as children, people who take cranberry products more than twice a day and women with frequent UTIs.

Another review from October 2012 in The Cochrane Database of Systematic Reviews, which reviewed 24 studies, had a less promising view of cranberries in the treatment of UTIs. The review concluded that cranberry juice and supplements don't prevent UTIs and suggested that many of the studies were low quality.



Given the side effects of cranberry tablets, and their evidently low efficacy in treating UTIs, you may want to reconsider taking cranberry tablets unless specifically recommended by a doctor.

Read more: List of Good Bacteria in Yogurt

Cranberry Tablet Benefits

The effects of cranberry tablets are not all negative. As mentioned, several studies in The Cochrane Database of Systematic Reviews point to the effectiveness of cranberry supplements or cranberry juice in preventing UTIs in specific groups, particularly in children, women with recurring UTIs and those who have cranberry products more than twice a day.


Bottom line: The jury's still out on whether cranberry tablets can be used in UTI treatment or prevention. It's best to consult a health care professional in order to determine whether the possible benefits outweigh the risks.

As is the case with many types of berries, cranberries contain essential vitamins, namely vitamin C. The 2012 review in Clinics, explains that cranberries contain high levels of vitamin C, about 200 milligrams per kilogram of fresh berries.

The USDA shows that cranberries also contain large amounts of potassium and vitamin A, as well as smaller amounts of calcium and magnesium.




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