A dry cough is a cough without phlegm. The human body is excited by the vagus nerve at night, so coughs are more frequent at night. The first is the body’s own disease, which has the following causes: 1. acute tracheobronchitis; tonsillitis; acute pharyngolaryngitis; acute attacks of chronic pharyngitis. The second is external factors, there are the following: 1, taking drugs that cause dry cough, for example, the angiotensin inhibitor captopril for hypertension can cause a dry cough. 2, long-term smoking, drinking, often eat spicy and irritating food, stimulating the respiratory tract and esophagus, inflammation of the throat, the overall immunity of the body is reduced, it will appear dry cough at night. 3, the environment in which the air is dry and dirty can also cause a dry cough. The suspended matter in the air is inhaled into the respiratory tract, and the respiratory tract’s own cleaning action causes a cough, which is a protective reflex. 4. The narrowing of the airway due to the sleeping position can also cause coughing. To sum up, there are many reasons for dry cough at night, both self-induced and external, so the problem should be analyzed specifically.