Try cranberry juice. New research suggests that the beneficial substances in cranberry juice could reach the urinary tract and prevent bacterial adhesion within eight hours. A mixture of cranberry juice, water, and sweeteners found in cranberry juice cocktail was used for the study because it is the most popular cranberry beverage. The researchers discovered that in petri dishes, cranberry metabolites in the juice prevented E. coli from sticking to other bacteria, limiting its ability to grow and multiply. If E. coli is able to connect with other bacteria, such as the bacteria found in the urinary tract, it forms a layer or "biofilm." This allows the bacteria to multiply and produce an infection.
A number of controlled clinical trials -- these are carefully designed and conducted scientific studies done in humans -- have concluded that cranberry juice really is effective for preventing urinary tract infections.
Cranberry juice may not kill the bacteria, but it does cause it to lose it's "stickiness" where it can flush out of the body.