If there is no sputum to cough up but some people still have coughing symptoms, it is more common to have airway inflammation, including acute upper respiratory tract infections, bronchitis, pneumonia and bronchiectasis, etc. Clinically, these diseases will produce a large amount of sputum and cough up. Clinically, due to these diseases, the inflammatory secretion of the corresponding airway mucosa will be exuded, and a large amount of sputum will be produced and coughed up, through the removal of phlegm, cough and anti-inflammatory and other standardized treatments, the symptoms of coughing sputum will be alleviated and completely disappeared. The main reason for the cough after cure is that although the inflammation of the airway mucosa is controlled and the inflammatory secretion disappears, the edema and congestion of the airway mucosa have not completely disappeared, and there is a repair time for it to return to the normal mucosal state, so coughing symptoms will still occur in the meantime.