Diarrhea and fever are associated with food accumulation, gastrointestinal flu, acute gastroenteritis, etc. Food accumulation is mainly found in children with incomplete spleen and stomach function. In the case of accumulation of food, the prolonged retention of food generates heat and leads to fever, and the discharge of rotten food into the intestine also causes irritation to the mucous membrane of the intestinal wall, thus causing diarrhea. Gastrointestinal flu is a disease caused by a viral infection that causes not only gastrointestinal symptoms but also flu symptoms, resulting in diarrhea and fever. During the attack of acute gastroenteritis, the patient will suffer from violent vomiting and diarrhea, and in severe cases, fever will appear due to the loss of a lot of water in the body and the lowering of the body’s immunity.