Pediatric diarrhea, or diarrheal disease, is a group of gastrointestinal syndromes caused by multiple pathogens and factors, characterized by an increase in the number of stools and changes in stool characteristics, and is one of the most common diseases among infants and young children in China. 6 months to 2 years old infants and young children have a high incidence, and about half of them are within one year of age.