There are many diseases that require vigilance for high fever, such as influenza, parasitic diseases, dysentery, typhoid fever, encephalitis, malignant tumors and connective tissue diseases. Hyperthermia is defined as a body temperature of 39.1℃ and above, which is a manifestation of the body’s systemic response to disease-causing factors. High fever can be seen in a variety of diseases, such as influenza, typhoid fever (salmonella infection), can lead to high fever. Intracranial tissue trauma is prone to infection and symptoms of hyperpyrexia. A few systemic malignancies such as leukemia can also present with fever. Connective tissue diseases such as juvenile rheumatoid arthritis and rheumatic fever can also present with high fever. If the fever does not go away for a long time, or if it does not improve with medication for a period of time, it is necessary to go to a regular hospital in time to do a comprehensive examination, such as blood routine, bone marrow aspiration, C-reactive protein, chest radiographs, tumor-associated antigens, rheumatoid factor, cranial CT, etc., and then, according to the results of the examination, to make a clear diagnosis, and then comply with the doctor’s instructions to standardize the treatment. Avoid blindly using medication on your own, so as not to delay the condition and the timing of treatment.