Until recently, the well known health benefits of cranberries were thought to be due to the high vitamin C content of the fruit. But now scientists have isolated other compounds present in cranberries which have the special effect of preventing bacteria from adhering to the urinary tract. These compounds, condensed tannis or proanthocyanidins, may be effective in preventing or easing urinary tract infections by preventing Escherichia coli (E. coli bacteria) from adhering to the kidney or bladder cells. (The New England Journal of Medicine, October 8th, 1998.)

In related research at Tel Aviv University it was determined that the same properties of cranberries reduce the amount or oral bacteria, thus reducing the formation of dental plaque and the resultant gum disease.