Infantile diarrhea, a gastrointestinal tract dysfunction in infancy and early childhood, is a syndrome characterized by diarrhea and vomiting, with the highest incidence in summer and autumn. Diarrhea often leads to malnutrition, multivitamin deficiency, multiple infections, and water-electrolyte disturbances, and impaired heart, liver, and kidney function. The causative factors of this disease are divided into three aspects: 1. Physical factors This disease mainly occurs in infants and young children, and its endogenous characteristics: (1) The gastrointestinal tract of infants is not mature enough, the activity of enzymes is low, but the nutritional needs are relatively more, and the gastrointestinal tract is burdened. (2) The neurological, endocrine, circulatory systems, liver and kidney functions are immature and poorly regulated during infancy. (3) The immune function of infants is also not perfect. Serum E. coli antibody titers are lowest from birth to 2 weeks of age and gradually increase later. Therefore, infants and children are susceptible to E. coli enteritis. The high E. coli antibody titers in breast milk, especially the high pathogenic E. coli secretory IgA in colostrum, make breastfed children less likely to develop the disease and less likely to become ill. Similarly, small infants have low antibodies to rotavirus, and when the same collective epidemic occurs, small infants have more disease. (4) The distribution of body fluids in infants is different from that of adults, with a high proportion of extracellular fluids and a strong water metabolism and poor regulation, making them more prone to fluid and electrolyte disorders. Infants are prone to rickets and malnutrition, which can easily lead to digestive disorders, and at this time, the intestinal secretion type IgA is insufficient, and diarrhea is easy to delay. 2, infection factors are divided into internal and external infections of the digestive tract, the former is the main. (1) infection in the digestive tract pathogenic microorganisms can enter the pediatric digestive tract with contaminated food or water, and therefore easy to occur in artificially fed children. Infections may also occur if the utensils used for feeding or the food itself are not sterilized or not sterilized enough. Viruses can also be contracted through the respiratory tract or water sources. Secondly, infection from adult carriers, who become asymptomatic intestinal carriers, can lead to pathogenic transmission. (2) Infection of organs and tissues outside the GI tract can also cause diarrhea, commonly in otitis media, pharyngitis, pneumonia, urinary tract infections and skin infections. Diarrhea is not serious and is more common at younger ages. The cause of diarrhea is partly due to digestive disorders caused by infections outside the intestinal tract, and partly may be caused by infections with the same pathogen (mainly viruses) both inside and outside the intestinal tract. (3) intestinal flora disorders long-term application of a large number of broad-spectrum antibiotics, such as chloramphenicol, kanamycin, gentamicin, ampicillin, a variety of cephalosporins, especially when two or more used, in addition to direct stimulation of the intestinal tract or stimulation of the vegetative nerve caused by increased intestinal peristalsis, reduced glucose absorption, reduced biosaccharidase activity and diarrhea, more serious is to cause intestinal flora disorders. At this time, the normal intestinal Escherichia coli disappeared or significantly reduced, while drug-resistant Staphylococcus aureus, Proteus mirabilis, Pseudomonas aeruginosa, Clostridium difficile or Candida albicans can proliferate, causing enteritis that is difficult to control by drugs. 3, digestive disorders (1) dietary factors. (2) Intolerance to carbohydrates. (3) Food allergy. (4) Drug effects. (5) Other factors: such as unclean environment, too little outdoor activities, sudden changes in lifestyle, sudden changes in the external climate (called “wind, cold, summer, wet diarrhea” in Chinese medicine), etc. are also likely to cause diarrhea in infants.