Cranberry juice (Vaccinium macrocarpon) is a widely used and recommended North-American folk remedy for prophylaxis of urinary tract infections (UTI). Clinical trials have documented its efficacy in women with recurrent UTI, but so far not in other groups of patients. The composition of effective cranberry products and its dosage in UTI prophylaxis have not been defined. Intriguing experimental research has identified an anti-adhesive mechanism of cranberry juice that prevents docking of bacteria on host tissues. This efficacy mechanism can be traced in patients' urine following oral intake of cranberry products and appears to be due to proanthocyanidins with an A-type linkage of flavanols. The application of this anti-adhesion mechanism of cranberry-proanthocyandins is currently also investigated in other common diseases of bacterial pathogenesis, for example Helicobacter pylori-associated gastritis and dental caries/periodontal disease. The use of cranberry products appears to be safe and provide additional benefits by anti-oxidant and cholesterol-lowering activity.