people who often get utis and who use spermicide or a diaphragm for birth control should use a different type of birth control. cranberry (juice or capsules) may decrease the number of infections, but some people cannot use cranberries for long periods of time. gastrointestinal (stomach) upset occurs in more than 30% of people who regularly drink cranberry juice or take capsules. as of 2011, probiotics used intravaginally (in the vagina) require further study to determine if they are helpful.