Four-year-old baby boy especially easy to cough may be inhalation of foreign bodies, persistent infection, allergic cough and other reasons. 1. inhalation of foreign bodies: four-year-old baby boy ate some small particles of foreign bodies, accidentally choking to the trachea, not timely removal of foreign bodies, foreign bodies have been stimulating the bronchial tubes, the baby will be easy to cough. 2. persistent infection: four-year-old baby boy with low immunity for a long time, infected with some viruses and special pathogens, such as mycoplasma, chlamydia, no symptomatic use of antibacterial drugs, may always have cough symptoms. 3. Allergic cough: four-year-old baby boy belongs to the allergic body, after contact with allergens, such as contact with fumes, cold air, shrimp, dust, causing airway surface hyperreactivity, mast cell secretion increased, airway spasm triggered cough symptoms, prolonged contact with allergens may be prone to cough. Four-year-old boy is particularly prone to coughing for a number of reasons, and serious cases are recommended to seek timely medical examination and treatment.