4-year-old children always cough, lungs, airways are fine, generally considered because of contact with external allergens, resulting in allergic cough. Clinical generally controlled by drug therapy, such as cough suppressants, glucocorticoids, antihistamines, etc., the specific treatment should be carried out under the guidance of a doctor. 1. Cough suppressants: When cough is severe and cannot be controlled by general drugs, central cough suppressants, such as dextromethorphan hydrobromide tablets and phenylpropylpiperine phosphate tablets, etc., can be used under the guidance of a doctor, and are not routinely used. 2. Glucocorticoids: such as prednisone acetate tablets, hydrocortisone acetate tablets, beclomethasone propionate suspension for inhalation. 3. Antihistamines: such as levocetirizine hydrochloride tablets, loratadine tablets and so on. Adverse reactions may occur during the taking of the above drugs, it is recommended to use the drugs under the guidance of a doctor, not blindly self-medication, in order to avoid adverse effects. If the patient’s cough symptoms are serious, or the symptoms continue without improvement, should go to the hospital in time to clarify the diagnosis for targeted treatment.