Fever is the body under the action of a variety of pyrogen or various causes of central thermoregulatory system dysfunction, resulting in the body temperature higher than normal. Normal human body temperature is generally 36℃~37℃, which can be slightly different due to different measurement methods. Various pyrogens that cause fever include exogenous pyrogens (bacteria, viruses, inflammatory exudates, necrotic tissues, antigen-antibody complexes, etc.) and endogenous pyrogens (interleukins, tumor necrosis factors, etc.), as well as intracranial injuries that result in damage to the thermoregulatory centers, which can also cause fever. The treatment of fever includes anticause treatment and symptomatic treatment. Anti-causal treatment includes anti-infection, anti-virus, removal of necrotic tissue, and removal of tumor. Symptomatic treatment includes physical hypothermia (warm water on the skin, artificial ice blanket) and medication (ibuprofen, diclofenac sodium, etc.). Watermelon, just a common fruit, does not contain any antipyretic drug ingredients and does not have any therapeutic effect on the cause of fever, so eating watermelon cannot reduce fever. Eating watermelon has no effect on reducing fever, fever, it is recommended to consult a doctor in time to find the cause of the disease, drugs need to be used under the guidance of a professional doctor.