Bifidobacterium is an important probiotic in the human intestinal tract, which has the functions of promoting gastrointestinal absorption and digestion, biological barrier function and regulating immunity. 1, promoting gastrointestinal absorption and digestion: Bifidobacterium can reduce the absorption of harmful bacteria, adjust the intestinal flora and prevent dysbiosis, so as to promote the role of gastrointestinal absorption and digestion; 2, biological barrier function: Bifidobacterium together with other anaerobic bacteria occupy the surface of the intestinal mucosa, forming a biological barrier to prevent the colonization and invasion of germs; 3, regulation of immunity: under normal circumstances, the microorganisms in the intestinal tract will form a relative balance of homeostasis, once the homeostasis is disrupted, it will cause dysbiosis, harmful bacteria multiply, causing diarrhea. Bifidobacterium can rebuild the normal micro-ecosystem in the human intestine, promote the improvement of diarrhea symptoms and signs, enhance the immune function in the gastrointestinal tract, and reduce the inflammatory response of the body, thus enhancing the immunity of the gastrointestinal tract. Patients are advised not to use the drug privately, and this drug should be used under the guidance of a professional doctor.