Pregnancy and breast-feeding: Cranberries and cranberry juice are safe to consume during pregnancy and breast-feeding. However, do not use dietary supplements that contain cranberry products. It is not known if these are safe to use during pregnancy and breast-feeding.
Aspirin allergy: Cranberries contain significant amounts of salicylic acid. Salicylic acid is similar to aspirin. Avoid drinking large quantities of cranberry juice if you are allergic to aspirin.
Inflammation of the stomach lining (Atrophic gastritis): Cranberry juice might increase how much vitamin B12 the body absorbs for people with atrophic gastritis.
Diabetes: Some cranberry juice products are sweetened with extra sugar. If you have diabetes, stick with cranberry products that are sweetened with artificial sweeteners.
Low stomach acid (hypochlorhydria). Cranberry juice might increase how much vitamin B12 the body absorbs for people with low levels of stomach acid.
Kidney stones: Cranberry juice and cranberry extracts contain a large amount of a chemical called oxalate. In fact, there is some evidence that some cranberry extract tablets can boost the level of oxalate in the urine by as much as 43%. Since kidney stones are made primarily from oxalate combined with calcium, healthcare providers worry that cranberry might increase the risk of kidney stones. To be on the safe side, avoid taking cranberry extract products or drinking a lot of cranberry juice if you have a history of kidney stones.
