Coughing at night but not during the day is considered to be the result of cough variant asthma, pharyngitis, and bronchitis. 1. Cough variant asthma: patients due to persistent airway inflammatory response and airway hyperreactivity and other reasons for chronic cough, commonly at night or in the early morning when coughing violently, for the stimulation of cough, so see the cough at night, the phenomenon of coughing during the day. 2. Pharyngitis: patients due to tobacco and alcohol stimulation, air pollution, gastroesophageal reflux and other reasons for inflammatory reaction of the mucous membrane of the pharynx, part of the patient due to less water at night or reflux severe and make the throat itch more obvious, which leads to night cough, so the phenomenon of cough at night, not cough during the day. 3. Bronchitis: patients due to bacteria, viruses and other violations of the upper respiratory tract and lead to the emergence of chronic non-specific inflammation of the bronchial tubes, some patients due to increased sputum production at night, stimulation of the pharynx and lead to nighttime coughing, so it can be seen at night coughing, daytime cough phenomenon. In addition to respiratory diseases can cause night cough, daytime cough phenomenon, such as improper sleeping posture, reflux esophagitis and other reasons can also cause the above situation. Once the phenomenon of coughing at night and not coughing during the day occurs, it is recommended to go to the hospital as soon as possible for examination and clear diagnosis.