No matter children or adults, diarrhea is very common. For the 3-year-old baby, diarrhea may be caused by the following reasons: first, the abdomen is cold. Second, dyspepsia and food accumulation are very common in children's digestive department. Third, infected with bacteria or viruses, causing acute gastroenteritis. Most cases of gastroenteritis in children are caused by viruses. No matter which case, first, to avoid severe diarrhea, smectite powder can be used as intestinal mucosal protective agent. 2、 Make up water and electrolyte to prevent dehydration. Mainly focus on these two points, and then apply probiotics in combination with specific situations. If it is caused by indigestion and food accumulation, and the abdominal pain is relatively serious, you can use Huaji Oral Liquid and Xingpi Yanger Granule.