Atlantablue.....They are essential bacteria that reside in our intestines which perform many good deeds for our well being...Help breakdown the foods along with acids and enymes to be absorbed across our intestinal villi. Keep yeast and other bad pathogens in check. Help in vitamin-B's absorption and help in any micro tears in the intestinal lining to keep bacteria and abnormal proteins from entering so there's a few examples on Probiotics.....