To determine whether a child has diarrhea, it is important to look not only at the increase in the number of stools, but also at the increase in stool volume and the change in the nature of the stool. If the number of bowel movements only increases and the stool is still formed, it is called pseudo-diarrhea. According to the causes of diarrhea, diarrhea is broadly divided into three categories: a. Physiological diarrhea. Some infants have yellow-green loose stools soon after birth, and the number of stools is also high, but they are in good spirits, do not vomit, and always have a good appetite, and the diarrhea disappears naturally as they grow older and after the addition of complementary foods. Children with physiological diarrhea are usually prone to skin eczema and elevated body temperature after ingesting allogeneic proteins such as milk or eggs, or even after being exposed to the sun, wind or rubbing of clothes. Second, indigestive diarrhea. Diarrhea caused in infancy, most commonly due to improper feeding, either eat too much, or eat too little; the weather is too hot, sudden cold; frequent transfer of new food, etc., can cause diarrhea due to indigestion. Indigestion diarrhea has symptoms such as fever, vomiting and loss of appetite. The stool is thin and mushy, egg-flake soup-like or water-like, even with mucus. Third, infectious diarrhea. Diarrhea caused by the invasion of bacteria, viruses or molds into the gastrointestinal tract is called infectious diarrhea. Most children with this type of diarrhea have fever, vomiting is not necessarily the main symptom, the stool has an unusual odor and contains mucus or pus and blood, and if left untreated, the diarrhea will continue or worsen. Because of the different pathogens that cause diarrhea, their diarrhea has its own characteristics, such as: 1, bacterial dysentery. Abbreviated bacillary dysentery, light often no fever or only low fever, increased stool, mixed with pus and blood; raw can suddenly develop high fever, pale, convulsions, cold limbs, pulse can not be felt, and even coma. Because the onset is very rapid, the intestinal lesions have not yet formed, the sick child not only does not have diarrhea, and sometimes can be constipated. It is very difficult to distinguish this kind of problem from meningitis and septicemia. We call it toxic bacillary dysentery. Infants within 1 year of age with difficult bacillary dysentery symptoms are often atypical, showing no fever or low fever, 3-5 times a day watery stools, easy to misdiagnose as indigestion. 2. Diarrhea caused by viruses (mostly rotavirus). Most of them occur in August-November each year, with a peak incidence in September. Also known as autumn diarrhea. Mostly seen in well-nourished infants aged 6-18 months. Autumn diarrhea has a rapid onset, with an elevated body temperature between 38-40 degrees Celsius, along with symptoms of cold production and diarrhea on the day of onset. The stool is like rice soup or egg drop soup, without a small amount of mucus. Because of the large amount of stool, which is often washed out like water, the sick child soon develops symptoms of dehydration such as sunken eyes and dry mouth and lips. Children have severe thirst and crying and restlessness. Campylobacter jejuni is one of the important stain-causing bacteria of pediatric infectious diarrhea in China, accounting for almost the second place in cases of sensory diarrhea, second only to dysbiosis. It can occur throughout the year, with peak incidence in summer and autumn, especially in children under two years old. Incubation period of 3-5 days, systemic toxicity symptoms are obvious, with high fever, vomiting and abdominal pain, followed by yellow watery stools with peculiar foul odor, there are a few mucus or pus and blood-like stools. 3, diarrhea caused by mold. Stool yellow thin or green, more foam, not mucus, beanbag-like, usually weak, malnourished or long-term antibiotics for children prone to occur.