There are many reasons that cause 3.5 year old babies to cough badly at night, which may be acute upper respiratory tract infection, allergic reaction, pneumonia and so on. It is important to choose a reasonable treatment according to the actual condition. 1. Acute upper respiratory tract infection: As 3 and a half year old babies have poor resistance, they are easily attacked by pathogenic microorganisms and have colds, which are usually accompanied by inflammation of the throat, and they will have a strong cough at night, which can be treated with medicines such as pediatric cough syrups under the doctor’s advice and guidance. 2. Allergic reaction: If the 3 and a half year old baby belongs to the allergic body, in the night sleep contact with cold air, dust, smoke and other allergens, will stimulate the mucous membrane of the respiratory tract, triggering allergic cough, can be under the guidance of the doctor, choose loratadine syrup and other anti-allergic drugs to relieve. Daily to avoid contact with allergens, to provide a safe and comfortable sleep environment for the baby. 3. Pneumonia: pediatric pneumonia, mainly by bacteria, viruses and other infections in the lungs of inflammation, the baby will appear in the night coughing, can also be accompanied by dyspnea, wheezing and other symptoms, the need for active anti-inflammatory treatment under the advice of the doctor. If the bacterial infection caused by should follow the doctor’s advice to choose cefixime and other antibacterial drugs. If the 3 and a half year old baby coughing at night symptoms, can not be effectively relieved, to go to the hospital in time for examination, symptomatic treatment, to avoid delaying the baby’s condition. The above drugs should be used under the guidance of a doctor.