It wasn't until the early 1900s that American researchers discovered that cranberries, especially its juice, could promote a healthy bladder and urinary tract. Since then it has been prized by herbalists and studied extensively by scientists with positive results. It appears cranberries contain an antioxidant called proanthocyanidins that work to keep the bladder healthy. Warning:: this product contains a Chemical known in the State of California to Cause birth defects or other reproductive harm.