Coughing is a normal physiological phenomenon, through coughing can clear the respiratory tract of foreign bodies or secretions, in addition there may be certain diseases caused by the respiratory system, cardiovascular disease and other factors. 1. Respiratory system diseases: When there are respiratory diseases, they are divided into respiratory diseases and pleural diseases. When there are diseases such as laryngitis, tracheobronchitis, bronchiectasis, etc., it will stimulate the tracheobronchial tubes, which will cause coughing and sometimes coughing up sputum. 2. Cardiovascular disease: When there are cardiovascular diseases such as left heart failure, pulmonary bruising or pulmonary edema can occur, followed by exudate, which needs to be discharged by coughing or coughing up sputum. 3.Neurological factors: When the skin, nasal mucosa, pharyngeal isthmus mucosa is irritated or when there is encephalitis or meningitis can also lead to stimulation of the nerves innervating the cough, resulting in symptoms of cough. 4. Other factors: Cough may occur when some medications are used. Gastroesophageal reflux disease can also cause cough. There are also habitual coughs and psychological coughs. After observing the cough for some time, if it still persists, it is recommended to go to the hospital immediately to avoid delay.