In general, if the symptoms of cough and fever occur repeatedly, you can first consider whether it is caused by pneumonia, for which fever, cough and sputum are typical symptoms. In addition, diseases such as tuberculosis and pulmonary embolism are also often manifested as cough and fever, which need to be diagnosed differently after completing relevant examinations. If the symptoms are severe, the patient should be alerted to the possibility of lung cancer and should seek medical attention in a timely manner to clarify the cause of the disease and provide symptomatic treatment. Pneumonia is a lung infection mainly caused by bacterial or viral infection, with cough as an early symptom, mainly manifested as recurrent dry cough, accompanied by clinical symptoms such as fever, fatigue and loss of appetite. The symptoms of recurrent cough and sputum may last for more than 2 weeks and cannot be relieved, with low fever in the afternoon and fever in a few patients. It may be accompanied by night sweats, fatigue, weight loss, and hemoptysis in a few patients; 3. Pulmonary embolism: it is commonly caused by thrombus dislodged and obstructing the pulmonary artery, which is mostly a recurrent dry cough, accompanied by fever and obvious symptoms of dyspnea and chest pain; 4. If the tumor invades the trachea, a high pitched metallic sound-like cough may occur. At the same time, if the tumor tissue is necrotic, it may also cause fever, accompanied by symptoms such as hemoptysis, weight loss, chest pain and dyspnea. In addition, if there is a non-infectious disease with pulmonary infiltration, such as lung injury caused by connective tissue disease, commonly seen in rheumatoid disease, systemic lupus erythematosus, vasculitis, etc., or lymphoma pulmonary infiltration, it can also cause patients to have recurrent cough and fever. Therefore, when a patient has symptoms of recurrent cough and fever, the first step is to do a lung examination, such as lung CT, which can help determine whether it is caused by pneumonia. Sputum bacterial cultures, mycoplasma antibodies, tuberculosis tests, and other non-infectious diseases should also be perfected to clarify the cause for symptomatic management.