There are many reasons why children do not cough during the day and cough at night, such as physiologic cough, upper respiratory tract infection, allergic cough, gastroesophageal reflux disease and so on. 1. Physiological cough: When the environment of dust, smoke or low temperature at night, stimulate the respiratory tract, can cause children to irritating cough. It is recommended to improve the environment in time. 2. Upper respiratory tract infection: Mostly caused by bacterial or viral infections, which can be accompanied by nasal congestion, runny nose, fever and other manifestations. Excessive secretion of phlegm at night and irritation of the airway when lying down lead to coughing in babies. 3. Allergic cough: the cause is not clear, mostly related to genetic factors. It is characterized by paroxysmal irritating dry cough, which often worsens at night. 4. Gastroesophageal reflux disease (GERD): Long-term reflux of gastric acid and gastric contents stimulates the pharynx and can lead to reflex cough. At night when you sleep lying down, stomach contents are more likely to reflux, causing cough. Children do not cough during the day and cough at night, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.