A fever of 38.5℃ is not a high fever, but a moderate fever. Fever is a phenomenon in which the body temperature rises above the normal range because the process of heat production and heat dissipation cannot maintain a dynamic balance under the action of thermogenic agents or when the body temperature center becomes dysfunctional. Usually, body temperature between 37.3℃-38℃ is low fever, 38.1-39℃ is moderate fever, 39.1-41℃ is high fever, and 41℃ or above is super high fever. Fever is a common clinical symptom and can be caused by a variety of reasons, such as fever caused by infections such as bacteria, viruses, Mycoplasma pneumoniae and fungi, or fever caused by malignant tumors, leukemia, heat stroke, extensive burns and other diseases. When patients develop fever, they should actively visit the fever clinic or general internal medicine department of the hospital to clarify the cause of the disease and then treat it symptomatically. In addition to medication as prescribed by the doctor, physical cooling can also be used at the same time, such as drinking more water, applying antipyretic patches or taking warm water baths.