The first symptom is a violent cough in children, as the foreign body chokes into the trachea and causes a reflex cough. The cough reflex is a protective reaction of the body to cough up the foreign body as far as possible. Secondly, a long-term chronic cough can occur. If the foreign body is deep and difficult to cough out, it can cause a chronic long-term cough that lasts for more than 4 weeks in children. In addition, it can cause breathing asymmetry in children. If the foreign body is blocked on one side of the large bronchus, it can cause the breath sounds on the affected side to be significantly lower, resulting in an asymmetry of breath sounds on both sides of the lungs of the child.