There is no stage of coughing; coughing is a protective respiratory reflex in the body, and its common causes include infections, physical, chemical, allergies, and other factors. There are many causes of cough symptoms, mainly the following five categories. 1. Infectious factors: ① upper respiratory tract diseases: such as colds, rhinitis, tonsillitis, acute and chronic pharyngitis, acute and chronic laryngitis, etc.; ② tracheal and bronchial diseases: such as acute and chronic bronchitis, bronchiectasis, etc.; ③ lung, pleural diseases: such as pneumonia, tuberculosis, pleurisy, etc.; ④ infectious and parasitic diseases: such as whooping cough, influenza, etc.. 2. Physical factors: ① respiratory obstruction: tracheal or bronchial foreign body, bronchial stenosis, bronchial tumor, pulmonary atelectasis, etc.; ② respiratory compression, esophageal diverticulum, esophageal tumors, lung tumors, lung cysts, tuberculosis, pneumoconiosis, pneumothorax, pleural effusion, pericardial effusion, pleural tumors and so on. 3. Chemical factors: inhalation of toxic and harmful irritant gases will stimulate the respiratory tract and cause cough. Commonly, there are smoking, inhalation of irritating gases (such as ammonia, chlorine, sulfur dioxide, ozone, etc.), but also in nitric acid, sulfuric acid, hydrochloric acid, formaldehyde and other volatile mist. 4. Allergic factors: allergic rhinitis, bronchial asthma, angioneurotic edema and so on. 5. Other factors: subphrenic abscess, diaphragmatic hernia, esophageal tracheal fistula, leukemia, Hodgkin’s disease and so on. When coughing occurs, it is recommended to go to the hospital in time to clarify the cause of the disease, and under the guidance of the doctor for treatment.