In addition to fever without any symptoms, most of the early manifestations of infectious diseases, has not yet appeared in other systems related symptoms, but with the progress of the disease, will gradually show related symptoms; a few patients may be tumors, connective tissue disease, etc.. Bacterial, viral, mycoplasma, chlamydia, fungal and other microbial infections, most of them are accompanied by fever, sometimes in the early stage of the disease is to fever as the main manifestation, there are no other accompanying symptoms. However, as the disease progresses, symptoms such as fatigue, headache, cough, abdominal pain, diarrhea, frequent urination and other related symptoms will gradually appear. Therefore, fever should be treated as early as possible, and the primary cause of the disease should be clarified through blood tests and treated as early as possible. High body temperature requires symptomatic application of physical cooling or medication to lower the temperature. A small number of patients may be due to tumors, systemic lupus erythematosus and other connective tissue diseases, fever, may be accompanied by other symptoms, such as the former have localized masses, the latter appear hair loss, joint pain and so on. Patients with fever are advised to seek medical attention as soon as possible.