Cough but no sputum clinically belongs to dry cough, according to the length of time is divided into acute dry cough and chronic dry cough. 1. Acute dry cough: often caused by the common cold, associated with repeated respiratory tract infections. Pathogenic microorganisms infecting the upper respiratory tract can damage the respiratory epithelium, making the respiratory tract more reactive and stimulating, resulting in a dry cough. 2. Chronic dry cough: in chronic dry cough, there are lung structural abnormalities of chronic airway diseases such as interstitial fibrosis, COPD (chronic obstructive pulmonary disease); there are also CT manifestations of normal, common AC (allergic cough), CVA (asthmatic variant cough). This type of chronic dry cough is mainly due to prolonged exposure to allergens that irritate the respiratory epithelium causing the patient to develop a cough. Another cause is due to gastroesophageal reflux disease (GERD), which usually occurs at night when the patient’s position changes after a visit to the doctor and often presents with chronic symptoms such as nocturnal cough. If coughing occurs, patients are advised to go to the hospital to find out the cause of the disease and not to use drugs without authorization to avoid adverse consequences.