Cough is a common symptom of respiratory diseases, and many kinds of diseases can cause cough. The following reasons are generally considered for coughing at night: 1. Lung problems, such as foreign bodies or tumors in the bronchi, can cause coughing to worsen after lying down due to irritation of the respiratory tract due to body position. Some patients are allergic to the environment in the room or to paint or furniture, which can also cause coughing at night. 2. Cardiovascular diseases, such as increased pulmonary stasis due to increased cardiac blood flow after lying down at night in patients with cardiac insufficiency, can also cause coughing all the time. If the patient always coughs at night, the patient should go to the hospital for further lung and heart examinations to clarify the cause.