What is Reuteri? Pronounced roy-tur-eye, this unique lactobacillus is naturally found in human breast milk, and is one of the first defenses a nursing mother passes to her child. When taken as a supplement, reuteri colonizes in the intestine and provides healthy benefits. Why take Primadophilus Reuteri? Multi-Strain Formula with lactobacillus and bifidobacterium to fortify both the large and small intestine microflora Prebiotic Support with NutraFlora scFOS (short-chain fructo-oligosaccharides) optimal food source for intestinal microflora True Potency - a guaranteed potency of at least 3 billion CFU through to its expiration date. Most other probiotic brands claim potency at time of manufacture.