â prevent urinary tract infections (UTIs and cystitis) â prevent kidney stones â kills bacteria and viruses. Cranberries increase the amount of âhippuricâ acid in the urine, and this is known to kill bacteria, leading to fewer occurrences of urinary tract infections. Simply drinking 1 to 2 cups of cranberry juice may help the prevention of cystitis, urinary tract and bladder infections. SUPPLEMENTS TO THE DIET. There are supplements that can be safely taken alongside the diet that are natural treatments for cystitis, bladder and urinary tract infections (UTIs).