Fever above 40℃ is considered as high fever, and persistent high fever can easily cause damage to the nervous system of the brain. Not timely cooling treatment will lead to disorders in the body temperature regulation center, triggering other adverse symptoms. More than 40 ℃ high temperature burn a night will cause a great impact on the body. First of all, the brain can cause damage, high heat can make the cerebral cortex overexcited or inhibited, irritability, convulsions, lethargy and other neurological damage. Second, it can damage the heart. Hyperthermia can cause the heart to beat faster, inducing arrhythmia, increasing the burden on the heart and causing heart failure. Hyperthermia can also trigger digestive problems, leading to a series of digestive symptoms such as loss of appetite, bloating and constipation. In addition, hyperthermia can lead to systemic disorders, such as dehydration, leg cramps, and dry mouth. Especially underdeveloped children, if there is no emergency treatment of fever, high fever maintained for more than half an hour, it may lead to the occurrence of limb convulsions, also known as febrile convulsions, sustained high fever of 40 degrees more than one night, may lead to irreversible damage. 40 degrees Celsius more than a night of fever on the human body is very harmful, easy to the whole body of various tissues and organs to cause damage, must be timely to the hospital, and actively give cooling treatment, and at the same time improve the relevant examination, such as routine blood, C-reactive protein, etc. Clearly infected with the type and location, according to the results of the examination to give the appropriate treatment.