Diarrhea after fever is common in some patients with acute gastroenteritis and gastrointestinal colds. If the patient has been in good health and has no underlying disease, timely rehydration after diarrhea can be self-healing. Patients with acute gastroenteritis often have an obvious history of unclean diet and may be accompanied by abdominal pain, diarrhea and even fever, nausea and vomiting. In this case, some antibacterial and anti-inflammatory drugs can be used. If the patient is older than 18 years old, quinolones such as norfloxacin are preferred; for patients with severe diarrhea, with dilute watery stools and no bacterial infection manifestations such as pus and blood mucus stools, montelukast can be added to stop diarrhea. In case of dehydration such as dry mouth, poor skin elasticity and panic, fluid should be replenished promptly. Oral rehydration salts can be chosen for mild to moderate dehydration, while intravenous rehydration is required for severe dehydration. If the patient’s body temperature is less than 38.5℃, supplemental fluids and physical cooling can be chosen. When it is greater than 38.5℃, acetaminophen or ibuprofen extended-release capsules can be chosen to reduce the fever. For patients with gastrointestinal flu, who often have a cold abdomen or external wind chill, oral patchouli oral liquid may be an option. Patients with fever accompanied by diarrhea generally recover quickly with no sequelae through regular treatment. If a patient has a high fever that does not subside, serious diarrhea, or even dehydration, it is necessary to go to the hospital in a timely manner, replenish sufficient fluids, reduce fever and temperature in a timely manner, and take some antibacterial agents if necessary.