Probiotics that regulate the gastrointestinal tract include Bacillus subtilis, Bifidobacterium, Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus acidophilus, etc. Bacillus subtilis is a kind of beneficial bacteria, the last species of Bacillus, which can help digest food, improve gastrointestinal function, and reduce the occurrence of digestive system diseases. Bifidobacterium is an important probiotic in the intestine. It can enhance the immune function of the intestinal system, improve the absorption and digestion of nutrients in the intestine, and also has anti-tumor effects. Lactobacillus casei is acid-resistant, which can not only enhance the body's resistance to viruses, but also help the intestinal system clear bacteria, so it has a conditioning effect on food allergies and acute diarrhea. Lactobacillus rhamnosus is an intestinal probiotic that not only regulates intestinal flora imbalance, but also promotes the growth and function of bifidobacteria. Lactobacillus acidophilus can release acetic acid and lactic acid, which have antibacterial effects on harmful intestinal bacteria. Therefore, it can inhibit the growth of harmful bacteria and promote intestinal digestion of food.