There is a range of variation in the normal stools of 2-3 month old infants. The stools of breastfed children are usually golden yellow, soft paste-like, uniform, with a sour smell; the stools of milk-fed children are pale yellow or earthy gray, hard paste-like often mixed with grayish milk flaps, some odor. The number of bowel movements per day also varies greatly, some 1-2 times, there are as many as 5-6 times, generally speaking, breast-fed children have more bowel movements. Possible pathogens cause: 1, rotavirus enteritis: autumn and winter occur more, by fecal-oral transmission can also be transmitted through the respiratory tract. Most of the 6-24 months infants and young children, the onset of acute, often accompanied by fever and symptoms of upper respiratory tract infection, no obvious signs of infection poisoning, stools more often, more volume, more water, yellow watery or egg-like stool. There is no fishy odor, accompanied by dehydration, acidosis and electrolyte disorders. Rotavirus infection can also invade multiple organs. The disease is self-limiting, the natural course of the disease is about 3-7 days, 1-3 days after infection, there is a large amount of virus from the stool discharge up to 8 days. 2, norovirus enteritis: the onset of the season for September-April, the age of onset 1-10 years, fever, respiratory symptoms, diarrhea, vomiting and other manifestations, stool volume is medium, thin stool, watery stool, is a self-limiting disease, lasting 1-3 days, stool and peripheral blood picture generally no special findings. 3, enteritis caused by virulent bacteria: mostly occurs in the summer, the light only increased stool times, light changes in the nature. Heavy stool frequent, large, watery, egg-like mixed mucus, microscopic examination without white blood cells, accompanied by vomiting, dehydration, electro-mediated and acid-base balance disorders. Self-limiting disease, natural disease 3-7 days. 4, invasive bacterial enteritis: year-round onset, mostly seen in summer. Rapid onset, high fever, convulsions, frequent diarrhea, mucus, pus and blood in the stool, fishy odor. Symptoms of toxicity may be present, with microscopic examination of large numbers of leukocytes and varying numbers of red blood cells. Fecal culture can find the corresponding pathogenic bacteria. Campylobacter jejuni can cause systemic symptoms, such as pneumonia, meningitis, endocarditis, etc., and sometimes misdiagnosed as appendicitis. Yersinia pestis small intestinal colitis occurs mostly in winter and early spring, and can cause lymph node enlargement, mesenteric lymphadenitis, and also sore throat and lymphadenitis. Salmonella typhimurium small intestinal colitis. 5, hemorrhagic E. coli enteritis: yellow watery stool at the beginning, then bloody stool, with a special odor. Stool microscopy with a large number of red blood cells, often without white blood cells. 6, antibiotic-induced enteritis.