Cranberry or any of its derivatives are not proven to prevent bladder problems or treat bacteria common to bladder infections, according to Drugs.com. As cranberry is not approved by the FDA to treat any ailment, its use is classified as alternative medicine. No regulated manufacturing standards are associated with cranberry.
Drugs.com recommends that an individual consult a doctor before taking cranberry or any of its related products. Those who have had kidney stones may not be able to take cranberry. Pregnant women are discouraged from this form of medicine without professional medical advice, as cranberry may be harmful to the unborn child.