A cough that doesn’t stop at midnight may be due to cough variant asthma, gastroesophageal reflux cough, upper airway cough syndrome, cardiac insufficiency, or other causes. 1. Cough variant asthma: this disease is essentially a kind of asthma, which may be characterized by worsening symptoms at night. Exacerbation of cough at night may be associated with increased vagal excitability at night. 2. Gastroesophageal reflux cough: patients with gastroesophageal reflux may experience worsening of reflux at night when they are lying down, which may cause incessant coughing. 3. Upper Airway Cough Syndrome (UACS): UACS may be caused by the backflow of nasal mucus into the throat. The symptoms may be more prominent at night when the patient is lying down, which may cause frequent coughing during the night. 4. Cardiac insufficiency. Most coughs are accompanied by chest tightness, but in a few cases it may be a simple cough. The increase in the volume of blood returned to the heart when lying down at night, and the increase in the excitability of the vagus nerve at night can lead to frequent coughing at night. 5. Other causes: it may be caused by respiratory tract infection, lung cancer and other related diseases. When coughing at night, it is recommended to consult a doctor in time to find out the cause.