The number of bowel movements per day may be different for children due to their age, diet, and bowel habits. Generally speaking, breastfed infants have 3-4 bowel movements per day, sometimes up to 4-6 times, with yellow or golden-yellow paste and no odor; milk-fed children have yellowish or earthy stools, which are slightly harder than those who are breastfed, 1-2 times per day. If a child’s stool frequency increases compared to the usual, the stool properties have changed that is diarrhea. Infants and young children have a poorly developed digestive system, less secretion of various digestive enzymes, lower vitality, poor tolerance of food can not adapt to the larger changes in food material and quantity, because of rapid growth and development, the nutrients required are relatively more, the digestive tract is heavier, often in a state of tension, easy to occur digestive disorders and diarrhea. In addition, children have lower acidity in the stomach than adults, poor antibacterial ability, and lower immunoglobulin and gastrointestinal secretory immunoglobulin A (sIgA) in the blood, making them susceptible to intestinal infections and diarrhea. Pediatric diarrhea can be caused by non-infectious and infectious causes. 1, non-infectious causes 1, improper feeding: mostly artificial feeding children, due to irregular feeding, too much or too little amount or inappropriate food composition, such as premature feeding of large amounts of starch or fatty foods, sudden changes in food varieties or weaning; 2, food allergies: individual children allergic to milk or certain food components can occur diarrhea; 3, certain components of food can not be digested: individual children can not digest the milk in the lactose in milk and diarrhea; 4, sudden changes in climate, abdominal cold to increase intestinal peristalsis can cause diarrhea. Second, infectious causes intestinal infection can be caused by viruses, bacteria, fungi and parasites, the first two are more common. The most common viral enteritis is rotavirus, which is the most common pathogen of pediatric diarrhea in autumn and winter; bacteria such as dysentery bacillus, Escherichia coli, staphylococcus and so on. Stool specimens should be kept for stool microscopy in all children with diarrhea, noting the presence or absence of leukemia and red blood cells. A high number of white blood cells or pus cells in the stool is often due to various invasive bacterial infections, including bacillary dysentery. There are two possibilities: viral or non-invasive bacterial infections; and non-infectious diarrhea. When infectious diarrhea is considered, stool bacterial culture and drug sensitivity testing should be done promptly, fungal culture if necessary, and virological testing if available.