Babies do not cough for no reason after they fall asleep. Coughing is usually caused by a cold or a cold and fever when the baby is not properly covered during sleep. From a medical point of view, the purpose of coughing is to expel secretions and foreign bodies from the respiratory tract, which is a defensive act of the baby’s body, but if the cough is so intense that it interferes with eating and sleeping, it loses its protective meaning. If a baby has a cough as soon as he or she goes to sleep, it may be caused by whooping cough or acute spasmodic laryngitis. Because these two diseases have a long course, coughing occurs especially at bedtime. Many parents close the windows and doors tightly to prevent their baby from catching a cold at night, and the lack of oxygen caused by the lack of air circulation in the room can lead to a cough. If your baby is always coughing at bedtime, it is important to identify the cause and treat it promptly. If it is a simple cough, you can follow your doctor’s instructions and use cough suppressants and antibiotics that are suitable for your baby. However, if the cough is accompanied by high fever, asthma, or difficulty breathing, the symptoms are more serious and need to be treated by a pediatrician in a timely manner.