There are more reasons for 3-year-old babies to cough, such as respiratory disease, cardiovascular disease, etc. When the cough is strong at night, you can use cough suppressants such as Pentoxyverine and Dextromethorphan. 1. Pentoxyverine can reduce airway resistance, so that smooth muscle relief to achieve the purpose of cough suppression, can be used for respiratory tract infections and other causes of dry cough. Occasionally, nausea, vomiting, rash and other adverse reactions. Use with caution in pregnant and lactating women. 2. Dextromethorphan is a central cough suppressant, which can be used for coughs caused by colds, bronchitis, laryngitis and pharyngitis. Causes of cough include respiratory diseases, cardiovascular diseases, pleurisy and so on. Common causative pathogens are bacteria, virus, mycoplasma, and antibacterial drugs such as cefixime, four seasons antiviral combination, azithromycin, etc. need to be given respectively. Cough caused by cardiovascular disease should be actively treating the primary disease. The above drugs need to be used under the guidance of a doctor. Those with severe coughs should consult a doctor in time for treatment of the cause.