There are many reasons why coughing is stronger at night than during the day, because different reasons cause coughing to worsen at night. First, in the case of patients with chronic bronchitis, it may be due to sputum irritation when lying down at night, which leads to a violent cough. Second, in patients with chronic pharyngitis, breathing with the mouth open during sleep can trigger airway spasms and coughing. There is also allergic cough. There is a type of cough called cough variant asthma, which is characterized by a nocturnal cough and a dry cough. It is recommended that patients improve their lung function to clarify the diagnosis; there is also the reason that patients may have postnasal drip symptoms, which can cause a significant increase in postnasal drip symptoms at night due to lying down, thus causing the cough to worsen; there is also gastroesophageal reflux. There is also chronic cardiac insufficiency in patients who lie flat at night, which aggravates pulmonary stasis and causes coughing. Therefore, the cause of coughing is different and the cause of nighttime aggravation is also different. It is recommended that patients take into account their own situation and come to the hospital to clarify the cause if necessary.