Cough more than three weeks need to be alert to the causes of cough, may be related to cough variant asthma, tuberculosis, bronchodilatation and other diseases, need to clarify the cause and active treatment. 1. Cough variant asthma: Cough variant asthma can be characterized by chronic recurrent paroxysmal cough, mainly dry cough, due to airway hyperresponsiveness. Commonly used inhaled glucocorticoids combined with adrenergic receptor antagonist therapy, such as budesonide formoterol powder inhaler. 2. Tuberculosis: coughing up sputum for more than two weeks is a suspicious symptom of tuberculosis, which may be accompanied by afternoon low-grade fever, night sweats, loss of appetite, fatigue and other systemic symptoms, and some patients may have hemoptysis, chest pain, dyspnea and other symptoms. If diagnosed with tuberculosis, anti-tuberculosis drugs such as isoniazid, rifampicin, pyrazinamide, etc. should be used. 3. Bronchial dilatation: Most patients have a history of recurrent respiratory infections, which leads to the destruction of the bronchial wall structure to form bronchial dilatation, which is mainly manifested by recurrent coughing, coughing up sputum, and hemoptysis may occur in some patients. Treatment is mainly symptomatic, and active prevention of infection is needed. If infection occurs, cefixime or moxifloxacin can be used empirically to fight infection. There are other reasons for coughing for more than three weeks. If the cough is unrelieved for more than three weeks or is accompanied by other symptoms, it is important to go to the hospital and have the cause clarified and then give targeted treatment.