Fever and diarrhea in toddlers may be caused by gastrointestinal flu, acute gastroenteritis and other reasons. 1. Gastrointestinal flu: Gastrointestinal flu is a kind of cold. Gastrointestinal flu is mainly caused by coxsackie virus infection, and the symptoms mainly include stomach distension, abdominal pain, vomiting and fever. 2. Acute gastroenteritis: Gastrointestinal diseases in young children are caused by bacterial and viral infections. Microorganisms can not only cause diarrhea in young children, but also cause systemic infections and toxic symptoms, often accompanied by fever, vomiting, abdominal pain and even impaired consciousness. There may be other causes of fever and diarrhea in toddlers, and it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy.