Among them Lactobacillus and Bifidobacterium species were most frequently cited and have been implicated in many human GIT disorders and have become commercially promoted to improve the health of the host. The mode of action of probiotics involves a mutual interaction with intestinal cells and other microflora present in the gut. In these two chapters, the influence of probiotics on digestion, absorption and barrier function, secretory functions and the postnatal maturation of intestinal mucosa are described
