咳嗽是机体的一种保护性反射,其作用是清除呼吸道分泌物、渗出物以及侵入呼吸道的异物、清除呼吸道刺激因子,是机体防止感染的一种防御反射。咳嗽超过3周无明显肺部疾患称为慢性咳嗽。由于慢性咳嗽病因很多,可单独存在也可合并存在,因此诊断比较困难。在临床上慢性咳嗽几乎均由 Cough is a protective reflex of the body, its role is to remove respiratory secretions, exudates and foreign body invades the respiratory tract, remove respiratory irritants, is the body to prevent a defensive reflex. Cough more than 3 weeks without significant lung disease known as chronic cough. Due to the many causes of chronic cough, may exist alone can also exist together, so the diagnosis is more difficult. Chronic cough in clinical almost all by