At the end of expiration, the sound of foreign body impacting on the tracheal wall and subsonic area can be heard at the trachea, which is one of the symptoms of foreign body in the trachea. Later, the active foreign body moves with the airflow and can cause paroxysmal cough and dyspnea. The larynx has a rich distribution of nerves, and when stimulated by choking and other foreign bodies, it produces a defensive firing cough, forcing the foreign body out, which plays a role in protecting the lower respiratory tract. Choking or throat tickling is more dangerous in children than in adults. There are two types of foreign bodies, endogenous and exogenous, depending on the source of the foreign body. The former is the obstruction of pseudomembranes, dry crusts, cheese-like necrotic material, etc. in the airway, while all the foreign bodies usually referred to as tracheobronchial foreign bodies are of exogenous origin, which are all objects inhaled by mistake through the mouth. Foreign body into the trachea and bronchus is related to the following situations. 1.Children like to grasp and eat food, and inhale into the trachea when crying or laughing. 2, children’s teeth are not well developed, chewing function is poor, can not chew harder food, coupled with the poor defense reflex function of the larynx, the protection is not sound. 3, laughing or working with food or goods in the mouth, inadvertently or laughing when accidentally inhaled into the trachea. 4, general anesthesia or coma patients, tracheal intubation may also be loose teeth or denture touched off and not found; in addition, vomit removal is not timely, can be inhaled into the trachea. 5, upper respiratory tract surgery, instrumentation instability, or excision of tissue suddenly slipped down the airway. 6, Psychiatric patients or those who attempt suicide.