Body temperature >37.0℃ is considered fever, between 37.0-38.0℃ is low fever, between 38.0-39.0℃ is moderate fever, 39.0-41.0℃ is high fever, body temperature >41.0℃ is super high fever, this kind of patients usually have serious condition and need timely treatment. Fever is divided into infectious fever and non-infectious fever, with infectious fever being more common, mainly caused by infections such as bacteria, viruses, mycoplasma, fungi or parasites. Non-infectious fevers include burns, leukemia or allergic diseases such as rheumatic fever, connective tissue disease or certain tumors, and hyperthyroidism can also cause an increase in body temperature. In addition, heat stroke or severe sleeping pill poisoning can also cause an increase in body temperature.