The causes of coughing at 3:00 or 4:00 a.m. include physiological phenomena, gastroesophageal reflux disease (GERD), and allergic reactions. 1. Physiological phenomenon: due to factors such as eating spicy and stimulating food before going to bed, indoor air conditioning all day long, stimulate the mucous membrane of the throat, the night air is too dry, which triggered the patient in the morning at three or four o’clock coughing symptoms. 2. Gastroesophageal Reflux Disease (GERD): Due to the relaxation of the lower esophageal sphincter, patients suffer from gastroesophageal reflux disease (GERD). At night, when the patient lies down, the stomach body is in horizontal position, the phenomenon of gastroesophageal reflux will be more obvious, and the reflux will stimulate the mucous membrane of the throat, triggering the patient to develop coughing symptoms. 3. Allergic reaction: If the patient is allergic, allergic to cold air, dust, etc., such as contact with these allergens, the respiratory tract will be stimulated, triggering the patient to cough symptoms, generally to the night cough obvious. Night cough can also be seen in other diseases, such as patients with frequent night cough or aggravation, it is recommended that patients go to the hospital in a timely manner to improve the relevant examination, to clarify the cause of the disease, and comply with the doctor’s instructions for treatment.