10 Probiotic Strains For Temporary Disruptions to Intestinal Balance* NOW Probiotic-10 offers a balanced spectrum of live organisms consisting of acid-resistant probiotic bacterial strains that are known to naturally colonize the human GI tract. * Probiotic bacteria are critical ...10 Probiotic Strains For Temporary Disruptions to Intestinal Balance* NOW Probiotic-10 offers a balanced spectrum of live organisms consisting of acid-resistant probiotic bacterial strains that are known to naturally colonize the human GI tract. * Probiotic bacteria are critical for healthy digestion, help maintain the integrity of the intestinal lining, support proper intestinal motility and participate in the detoxification process.