When a fever persists for more than 10 days, it is recommended to go to the hospital immediately for an examination to identify the location of the infection. The most common causes of fever are bacterial infections and viral infections, especially those caused by bacterial infections. For example, if a patient has fever due to recurrent coughing and sputum, it should be considered a respiratory disease. If the patient has abdominal pain, diarrhea, or other gastrointestinal symptoms, the patient should be alerted to the possibility of gastrointestinal infections, especially pelvic and abdominal infections. If the patient has headache, loss of consciousness or decreased consciousness, it is also necessary to be alert to the presence of intracranial infections, which can be differentiated by further improvement of cerebrospinal fluid testing. Routine blood tests can be performed to distinguish between bacterial and viral infections. Then, according to the above-mentioned accompanying symptoms to distinguish to find the patient’s foci of infection, and after clarifying the cause of the disease to carry out targeted anti-infection treatment to achieve effective purposes.