Indigenous peoples have used cranberry preparations to treat urinary tract infections (UTI) and other illness for centuries. Modern medical research has revealed the chemical and physiological effects cranberries have on the urinary tract and just how drinking cranberry juice may help prevent urinary tract infections.

Cranberries contain proanthocyanidins (PACs), which inhibit the fimbrial adhesion of bacteria ^1,17, including Escherichia coli, to the urinary tract epithelium and hence the subsequent reproduction required for infection. It is these unique compounds that are pivotal in the prevention of UTI rather than the acidification of the urine as was previously hypothesized ^7,8,10.

Dr. Amy Howell et al. first reported on cranberry PACs antiadhesion properties in 1998. In 2002, at the Experimental Biology conference, it was reported that an eight-ounce serving of cranberry juice cocktail prevented E. coli from adhering to the bladder cells in the urine of six volunteers. Findings published as a research letter in the June 19, 2002 edition of the Journal of the American Medical Association reported that not only are cranberry PACs able to inhibit the adhesion of antibiotic susceptible bacteria, but resistant strains as well. The authors also report that the antiadhesion effect can last up to 10 hours after consumption, suggesting that two servings of cranberry juice cocktail a day, consumed at appropriate intervals, may be more beneficial than one.