The Vitamin Shop Acidophilus & Bifidus - 5 Billion Active Cells - Contains three strains of probiotics to assist with the maintenance of normal intestinal health: Lactobacillus rhamnosus, Lactobacillus acidophilus, and Bifidobacterium bifidum. Friendly or probiotic bacteria toil 24 hours a day, holding at bay and dominating the many pathogenic bacteria, viruses, yeast, and other microorganisms that unavoidably inhabit the intestinal tract. Given opportunity, the pathogens succeed in colonizing by adhering to the intestinal tract, inflicting disruptions to our intestinal health and throughout the whole body. Supplementing with Lactobacillus and Bifidobacterium will crowd out unwanted bacteria by repopulating the gastrointestinal tract.