FIGHT BACK AGAINST UTI'S!!! Stop the cycle of one UTI right after another. Don't just wait until they happen, take an antibiotic, and then have another one a short time later. Be proactive and prevent UTI's in the first place! CLINICALLY PROVEN Scientific studies have consistently shown that the proper type and amount of cranberry extract is effective in preventing urinary tract infections in a variety of patient populations. Research has proven that the active ingredient in cranberries is proanthocyanidins, or PACs, and that 36 mg is the required amount to be effective in the urinary tract.