Vaccinium macrocarpon (also called Large cranberry, American Cranberry and Bearberry) is a cranberry of the subgenus Oxycoccus and genus Vaccinium. It is native to North America (eastern Canada, and eastern United States, south to North Carolina at high altitudes).
The Mayo Clinic website gives a long list of conditions for which cranberry juice has been said to be beneficial; in almost all cases it does not support these suggestions, usually not rejecting them out of hand, but saying that more research is needed, or words to that effect.