There are many causes of coughing during the day but only at night, the common ones include allergic cough, chronic bronchitis, chronic cardiac insufficiency, gastroesophageal reflux and so on. 1. Allergic cough: allergic cough patients with increased airway sensitivity, compared with the daytime peak expiratory flow rate decreased, especially in the inhalation of cold air at night, pungent odors, or cotton wool, mites are more likely to be stimulated by cough symptoms. 2. Chronic bronchitis: chronic bronchitis patients, in the daytime phlegm can be discharged with the movement of the body, but at night during sleep, due to the weakening of phlegm expectoration, a large amount of phlegm accumulated in the lumen, coupled with the night airway reactivity enhancement, so part of the patients are more prone to cough at night. 3. Chronic cardiac insufficiency: the patient lying down the state of the return blood volume will increase significantly, so it will aggravate the pulmonary stasis, compared with the daytime standing state, it will be more prone to coughing. 4. Gastroesophageal reflux disease (GERD): when sleeping at night, duodenal and gastric contents will be refluxed into the esophagus, and the airway will be stimulated by this, so coughing or even choking will occur. There are many other reasons for not coughing during the day, but only at night, such as post-nasal drip syndrome, etc. If the symptoms do not improve, it is important to consult a doctor as soon as possible to avoid delaying the condition.