Does cranberry juice stop cystitis?

All 24 studies involved a group of people taking some kind of cranberry product, whether in juice, capsule or extract form, for a least a month. If you took all these studies into account, cranberries were no more effective than drinking extra water, a placebo or even doing nothing. The review authors concede that some small studies showed an effect, just as the previous review found, but when they factored in the results of the newest and largest study, the net result was different to the previous review.