The main clinical symptoms of bronchitis are coughing up phlegm, and in severe cases, chest tightness and shortness of breath. Some severe cases may also be complicated by obstructive pulmonary emphysema with dyspnea. 1. Cough and sputum: patients with bronchitis, usually due to pathogenic bacteria stimulation of the mucosa of the trachea edema and congestion, increased secretions, thus causing cough and sputum. Cough in the morning mainly, sleep with paroxysmal cough, sputum is usually white mucus or plasma foam, occasionally with blood. 2. Chest tightness, shortness of breath: wheezing may be accompanied by bronchial asthma. If accompanied by emphysema, shortness of breath after activity. When accompanied by bronchospasm, chest tightness and shortness of breath may occur to varying degrees. 3. Dyspnea: If the airflow is restricted by bronchitis, it may cause obstructive emphysema, which may lead to dyspnea and other symptoms. Patients with bronchitis should actively go to the hospital for treatment if the above symptoms occur.