B. infantis is isolated from the intestinal flora of breastfed, healthy infants. It is an anaerobic, gram-positive, bacterium. It is most abundant in infants since its numbers decline as we age. This decrease of probiotic bacteria, especially B. infantis, is closely related to the growth of pathogenic bacteria, diarrhea and other gastrointestinal diseases. Maintaining essential populations of B. infantis is critical to the suppression of harmful bacteria growth, the enhancement of infant immune function, and the reduction of infant diarrhea.