6 Probiotic Strains 20 Billion – Live Probiotic Cultures** Optimal Balance Formula Dietary Supplement Guaranteed Quality- Laboratory Tested Advanced Support for: Digestion Intestinal Flora Immune Function **20 billion per serving guaranteed at time of manufacture. 21st Century Advanced Probiotic synergistically combines 6 genetically distinct and beneficial probiotic strains and the prebiotic Inulin to support probiotic activity in the intestines. 21st Century offers the highest quality ingredients produced to strict standards for support of your good health.