Natural Factors Big Friends Children's Multi Probiotic - Contains seven species of bacteria that reflect the natural intestinal flora of healthy children. It provides live microorganisms that temporarily modify gut flora to maintain digestive health and support immature gastrointestinal systems. Big Friends Powder Multiprobiotic is made from a synergistic mix of resident and transient probiotic strains, with over half composed of bifidobacteria because it is the dominant family of good bacteria in children. This includes Bifidobacterium infantis, found specifically in human intestinal flora.