Cranberry for UTI Prevention

Cranberry has been used medicinally since the 17th century, and Native Americans used it extensively to treat bladder and kidney problems. According to the Mayo Clinic, studies have not shown cranberry to be an effective treatment for urinary tract infections (UTIs), but it may help prevent the infections from occurring in the first place.


There have been several studies on the effectiveness of cranberry juice or capsules to prevent UTIs. Many of the studies were sponsored by cranberry juice manufacturer Ocean Spray, and no single study has produced conclusive results to prove that cranberry juice or supplements can prevent the occurrence of urinary tract infections. However, the Mayo Clinic asserts that the combined outcome of the studies, along with other research, supports the use of cranberry as a method of UTI prevention. Cranberry may help prevent bacteria from clinging to the cells that line the bladder, making urinary tract infections less likely.


The Mayo Clinic recommends 3 oz. to 16 oz. of cranberry cocktail or about ½ oz. to 1 oz. of unsweetened pure cranberry juice per day for UTI prevention purposes. Other forms of cranberry that have been used in UTI prevention research include capsules, tinctures and concentrate. Between one and six 300 to 400 mg capsules of cranberry juice extract twice per day before or after meals is the Mayo Clinic’s recommended dose. Up to 1½ oz. of frozen cranberry juice concentrate twice per day and cranberry tinctures taken three times a day have also been used in UTI research. All of the Mayo Clinic’s dosing guidelines are for otherwise healthy adults who are 18 or older. Check with your doctor before adding cranberry to your daily routine.


While cranberry is considered very safe with few side effects or problems, some people should not take cranberry. Avoid using cranberry as a method of UTI prevention if you are allergic to cranberries or blueberries. Check with your doctor if you are allergic to aspirin or if you take blood thinners or aspirin on a regular basis. Large quantities of cranberry juice can cause allergic reactions in people who are allergic to aspirin. Choose sugar-free cranberry juice if you are diabetic or glucose intolerant to avoid a high spike in blood sugar levels. Large amounts of cranberry can cause gastrointestinal discomfort and diarrhea. Cranberry may increase the chance of developing kidney stones in people who have had oxalate stones in the past. If you are pregnant or breastfeeding check with your doctor to determine a safe form and dose of cranberry.

Cranberry has been used medicinally since the 17th century