Cough is a defensive reflex of the body and a symptom and reflection of a disease. Coughing at night instead of during the day is often seen in the following cases: 1. Cough variant asthma, which often occurs at night or is more pronounced at night due to the excitement of the vagus nerve, leading to further contraction and spasm of the bronchi, and can be manifested as no cough during the day but only at night. 2. Reflux esophagitis, which is more likely to occur at night due to the reduced tension of the esophagus when lying down. When the stomach contents reflux into the throat, it irritates and causes coughing, so it often manifests as no coughing during the day and coughing at night.3. Chronic cardiac insufficiency, mostly seen in elderly patients with hypertension and coronary artery disease, causes coughing to occur due to increased cardiac return blood volume and increased cardiac load when lying down at night, which causes pulmonary stasis symptoms.4. Other factors such as allergic cough, exposure to mites in the bedding at night, can easily Allergic cough is triggered by exposure to mites in the bedding at night, which can easily cause allergic cough, and drug cough such as when taking captopril, which reaches its peak concentration at night and therefore tends to cause symptoms of coughing at night.