Lactic acid bacteria "probiotic" is the most important group, defined probiotics as "one or a plurality of kinds of microorganism which can enhance the quality of the intestinal flora of humans or when fed to animals." Lactic acid bacteria can enhance the quality of the intestinal plexus mechanism of action may be (1) the production of organic acids, lower intestinal pH, (2) competition nutrients and harmful bacteria, (3) attached to the intestinal epithelium, the proliferation of places to reduce harmful bacteria, (4) produce antibacterial substances. Fishing effect of lactic acid bacteria to play, must be able to take it for granted given the intestinal tract. There are many 酦 fermented milk or intestines with the use of lactobacillus isolated from human intestines out of lactic acid bacteria in the human body in order to enhance its fixed significant. Many clinical trials have confirmed that there is indeed such a good Lactobacillus intestines effect, and indeed will reduce intestinal bad fungus. Lactobacillus immunomodulatory function highly valued, and it is generally believed that the cell surface polysaccharide concerning whether or lactic acid bacteria produce substances through the intestinal epithelial cells and how the immune system of the host of the impact? Although it is still unclear diverted, but studies show bacteria such as Lactobacillus bacteria through the intestinal Peyer patch area and into the blood or lymphatic system. On the other hand, perhaps the production of lactic acid bacteria or substances do not have to leave the intestine, can modulate the immune response, the recent discovery of intestinal cells when exposed to certain bacterial cell, which will increase as interleukin 8, tumour necrosis factor  and other proteins gene expression, and these substances are known to activate macrophages, thus enhancing the immune response