The 3-year-old baby sleeps at night coughing with phlegm, consider may be acute upper respiratory tract infection, sinusitis, pneumonia and so on cause, can take general treatment, medication and other treatments. 1. Acute upper respiratory tract infection: when a baby has an acute upper respiratory tract infection, it can be accompanied by coughing and phlegm, at this time, you can use aminobromine to resolve phlegm, and combined with bacterial infections, you can use cefaclor and other anti-infectious. 2. Sinusitis: the nose can have more purulent secretions, in the sleep of the purulent secretions from the back of the nasal cavity dripping into the throat, resulting in irritation choking and coughing, you can regularly use physiological saline nasal wash. 3. Pneumonia: Coughing with sputum is a typical manifestation of pneumonia, often accompanied by wheezing, shortness of breath, fever and other symptoms. Pneumonia with phlegm can use aminobiotics to resolve phlegm; if it is mycoplasma infection, you can consider using azithromycin and other anti-infective treatment. 3-year-old baby sleep cough at night, there may be other reasons, it is recommended to consult a doctor in time to identify the cause, the cause of treatment, the above medication as prescribed by the doctor.