Pomegranate juice has been shown to kill prostate cancer cells - in a test tube. But there's little reason to think that the juice has the the same effect inside a man's body. "If you are at high risk for the disease, you could try it," Dr. Lepor says of pomegranate juice. "But try it without a false sense of expectation." In any case, he says, the juice should be considered a complement to conventional treatments - not a substitute.