1. What is diarrhea in children? Diarrhea in children refers to an increase in the frequency of defecation in children, a decrease in the amount of stool, a thin or watery texture, and is accompanied by varying degrees of abdominal pain, bloating, nausea, vomiting and other symptoms. Common pathogens include bacteria, viruses and parasites. 2. Common causes of diarrhea in children 1. Digestive infection: such as E. coli infection, salmonella infection, etc. 2. Viral infection: such as rotavirus, norovirus, etc. 3. Parasitic infections: such as roundworms, hookworms, etc.