Causes of diarrhea in children Diarrhea in children refers to the symptoms of diarrhea in children, which is characterized by thin stools, increased frequency, and sometimes accompanied by vomiting, fever and other symptoms. There are many causes of diarrhea in children, such as intestinal infection, food allergy, abnormal intestinal immune system, etc. Intestinal infection is the most common cause, usually caused by viruses, bacteria, parasites, etc.