Physical cooling is the most simple, effective and safe way to reduce fever in addition to medication. General fever does not exceed 38.5 ℃, the first choice of physical cooling methods to reduce fever, mainly including ice packs, cold wet compresses and alcohol baths and other methods. If the head and back are still very hot after physical cooling, the following reasons are mostly considered: 1, the physical cooling method is not correct, the cooling effect has not been achieved, such as the location of the ice packs is not accurate, alcohol wipe only gently wipe the surface of the skin, etc.; 2, failure to grasp the timing of cooling, most patients in the high fever before the accompanied by chills or chills, this time to give the cold stimulation, on the contrary, it will increase the contraction of muscles, so that the increase in heat production; 3, fever The cause of the diagnosis is wrong, such as belonging to the fever caused by infectious diseases, take physical cooling is ineffective; 4, may be because of the body inflammatory reaction, fever for a long time, such as purulent tonsillitis, acute pharyngitis, dengue, influenza and other diseases. Some severe pneumonia, liver abscess, brain abscess, as well as immunocompromised, diabetic patients after infection, fever lasts longer, even to more than a week. Fever is a self-defense mechanism of the body against exogenous invasion, and if the inflammatory state of the body is not lifted, the body temperature often fails to return to normal levels. Prolonged fever can lead to rapid depletion of nutrients in the body, symptoms of low metabolism, and may also induce nerve damage, and in severe cases, brain cell necrosis. Therefore, if the head and back are still very hot after physical cooling, it is recommended that patients and their families consult the hospital, cooperate with the doctor to do the relevant tests, auxiliary examination, try to clarify the cause of the disease at an early stage, and then take appropriate treatment measures.