What is Cranberry? Cranberry is a member of the same family as bilberry & blueberry. The cranberry fruit is rich in minerals, including significant amounts of potassium, copper, magnesium, calcium, phosphorus & iron. Iodine gives Cranberries their ruby red colour. Naturally rich in the antioxidant A & C vitamins, they also contain traces of many B vitamins. But, it is cranberrys high organic acid content that is its most active ingredient. What Does Cranberry Do? May help to support a healthy urino-genital tract, kidneys & bladder by maintaining a healthy balance of bacteria.