Fever is a very common symptom in children, and once a child’s temperature is found to rise, parents rush to reduce the child’s fever to bring it down, which can prolong the course of the child’s illness. The degree and type of fever is an important indicator of the cause of the illness. If the cause of the fever is diagnosed before the forced cooling with drugs, it is tantamount to supporting the pathogenic role of the pathogen, making the child more ill. A. The two main causes of fever 1. Infectious fever: Fever is a defense response of the body to infection and is the most common. Fever caused by infectious diseases, there are bacterial, such as tonsillitis, sepsis, etc.; there are also viral, such as type B encephalitis, influenza, etc.; there are also parasitic diseases, such as malaria, etc. 2, non-infectious fever: non-infectious diseases cause a lot of fever, metabolic diseases such as: rheumatic fever, drug fever, vaccine reaction; a large number of tissue necrosis or destruction, such as large burns, acute hemolysis, Vascular embolism, leukemia, malignant reticulocytosis, Hodgkin’s disease, malignant lymphoma and other malignant tumors, etc. Hyperthyroidism, hyperadrenocorticism, congenital ectodermal dysplasia, summer fever, cerebral hemorrhage, etc. can also cause fever. The fever is the first symptom of many diseases, so do not rush to reduce the fever for your child before a clear diagnosis is made. Studies have proven that various immune functions in the body are “activated” during fever, and are more responsive than when the body temperature is normal, as evidenced by increased metabolism, increased antibody synthesis and enhanced phagocytic activity. These immune functions can inhibit the growth and reproduction of pathogens and facilitate the patient’s recovery, so it is a “protective wall” in our body. At the same time, the fever, fever duration, and fever type that the body exhibits when “attacked” by different pathogenic microorganisms vary, reflecting the changes in the disease. Therefore, fever manifestations are used as an important reference for diagnosing diseases, evaluating the efficacy and estimating the effects. Therefore, when it is not clear what the root cause of the fever is, if we rush to forcefully lower the temperature with drugs, not only will the antipyretic itself have side effects, but also frustrate the natural defense ability of the body, support the pathogenic effect of the pathogen, prolong the course of the disease, and may mask the symptoms due to the fever reduction, causing difficulties in the diagnosis of the primary disease and delaying the treatment. The right thing to do is for parents to take their child to the hospital right away and have blood tests done. Based on the test results, the doctor will tell you what might be causing the fever. Knowing what is going on, parents don’t have to worry