While there are a few studies that show that cranberry juice may reduce the number of symptomatic UTIs, most show that there is no difference in UTIs in women who drink cranberry juices versus those that do not. Therefore, cranberry juice cannot be recommended for the prevention of UTIs. There is some data that cranberry extract pills maybe more effective, however, this also needs further study. Cranberry juice often times contains large quantities of sugar and can worsen other health conditions. If you are worried about recurrent bladder infections, talk with your doctor!
Cochrane Database of Systematic Reviews, 4/2013