Is drinking too much cranberry juice bad?

Watch out for sugars: Cranberry juice is a great source of antioxidant flavonoids. Besides its fame for helping treat uti's it may prevent & even reverse cardiovascular disease. But it is rather tart & many have added sugars which are not healthy- some are even sweetened with high fructose corn syrup, which is best avoided. Look for ones without added sugars (some are blended with sweeter juices like grape- that's ok).

Cranberry juice: Large amounts of cranberry juice can cause GI upset. Limit or avoid use with warfarin. It also contains sugar.