Fever may be caused by physiological reasons, microbial infections, tumors and other causes. Fever may cause gastrointestinal peristalsis to slow down and pepsin activity to decrease nausea, vomiting, acid reflux, heartburn and other symptoms. 1. Physiological reasons: exercise, exertion, diet and other triggers may lead to a mild increase in body temperature, which is a normal physiological phenomenon and generally has no effect on the stomach. 2. Microbial infections: Bacterial, viral, mycoplasma and other microbial infections lead to abnormalities in the thermoregulatory center and fever symptoms, which may lead to gastrointestinal peristalsis and pepsin activity to reduce the appearance of indigestion, nausea, acid reflux, vomiting and other gastric symptoms. 3. Tumor: Gastric cancer, lung cancer, leukemia and other tumor diseases may cause fever due to cell necrosis and absorption or affect the thermoregulation center. Stomach symptoms such as acid reflux, heartburn, nausea, vomiting and so on may also appear due to affecting peristaltic movement of stomach and activity of digestive enzymes. Fever is recommended to consult a doctor in time to identify the cause of the disease with the help of the doctor, and to carry out targeted treatment or therapy.