Is your child having an upset stomach and belly cramps? These health issues could be signs of gastroenteritis. Well, the term gastroenteritis can be also defined as stomach flu. It is a common disease in kids that causes diarrhea, vomiting, and stomach pain. Most cases may last for several days without turning serious. Children can get better with plenty of rest and intake of liquids at home. However, acute gastroenteritis may need hospitalization.