Cranberry only contains a fraction of active ingredients, most of it is different inactive compounds such as fiber, acids, and other organic compounds. So with cranberry you never really know how much active ingredient you are actually getting. With ClearTract you get 100% active ingredients, which is why there is such a dramatic difference in taking ClearTract versus cranberry.
Leading practitioners of integrative medicine are now recommending d-mannose. Dr. Ronald Hoffman MD. Director of the Hoffman Center and host of the popular radio show Health Talk recommends it. Dr. Jacob Teitelbaum, director of the Center for CFS/FM therapies is another prominent supporter of d-mannose.