Proprietary Blend of 3 Strains: This proprietary blend of 3 clinically tested strains of good bacteria contains*: Lactobacillus gasseri KS-13 - to support nutrient absorption and lactose digestion. Bifodbacterium bifidum G9-1 - to help guard against occasional intestinal disturbances. Bifidobacterium longum MM-2 - to help keep your digestive system running smoothly, while supporting your overall immune system. Guaranteed Through Shelf Life. Probiotics need to be alive to be effective, not only at the time of manufacturing, but also at the end of their shelf life. Phillips' Colon Health Probiotics, unlike other leading competitors, guarantees 1.5 billion live bacteria CFUs at a specified expiration date. What are probiotics? Probiotics are live microorganisms, and are like those that naturally occur in your body. They normally live in the digestive tract and have played a role in your body's healthy immune system since you were born. Scientific evidence shows that probiotic species like Lactobacillus and Bifidobacterium help defend against occasional constipation, diarrhea, and gas.