Fructooligosaccharide (FOS) is a kind of probiotic proliferating agent, which is not digested and absorbed by human body, directly reaches the large intestine and rapidly proliferates Bifidobacterium in the intestine. It can not only improve the intestinal flora, but also inhibit the rise of blood glucose, promote the absorption of trace elements, inhibit the growth of harmful bacteria and improve immunity. Fructooligosaccharide (FOS) has been proved to be the only natural ingredient with the biological characteristics of super bifidogenic factor and water-soluble dietary fiber. It has been recognized by more than 200 countries and regions around the world.