Cranberry has long been regarded as an effective home remedy for the prevention and treatment of UTIs and has been extensively evaluated in clinical trials.

Contrary to popular belief, the effectiveness of cranberry is associated with its polyphenol content, specifically A-linkage Proanthocyanidins or PACs and has nothing to do with acidifying the urine.

In the first randomized, double-blind study examining whether cranberry juice consumption could prevent the recurrence of UTI, women in a nursing home consumed 300 ml/d of artificially sweetened cranberry juice for 6 months. After 1 month, the prevalence of bacteriuria with pyuria was significantly lowered for the women who had consumed cranberry juice.

Among women undergoing elective gynecologic surgery involving urinary catheterization, the use of cranberry extract capsules during the postoperative period reduced the rate of UTI by half.

While some studies have shown disappointing results, it is likely due to non-standardized levels or heat destroyed PACs in the preparations. There is solid evidence that intact A-linkage proanthocyanidins (PACs) found in cranberries act as powerful bacterial anti-adhesion molecules.