Now Probiotic-10 25 Billion is a dietary supplement that can provide you with a blend of highly potent and beneficial bacteria that can aid in digestion and support a healthy gastrointestinal system. When taken on a regular basis, this helpful probiotic formula can help you to maintain a healthy intestinal flora. Now Probiotic-10 25 Billion also contains FOS which is useful in the growth of acidophilus and bifidus organisms.