咳、痰、喘是呼吸道疾病的常见症状,三者常常同时存在。并互为因果,在对症治疗上也有因果联系。如呼吸道积痰可引起咳嗽,也可阻塞细支气管引起喘息,还能招致继发感染。加重症状。因此,祛痰药在促使痰液排出的同时,也起到一定的止咳、平喘作用。支气管痉挛和粘膜水肿主要引起喘息,而且因呼气阻力增加的刺激而致咳嗽:又因细支气管痉挛造成管腔闭塞,加重了排痰困难。因此,平喘药也有利于止咳 Cough, sputum, asthma are common symptoms of respiratory diseases, the three often exist at the same time. And each other cause and effect, symptomatic treatment also has a causal link. Such as sputum can cause respiratory tract cough, bronchial obstruction can also cause wheezing, but also lead to secondary infection. Increase the symptoms. Therefore, expectorant drugs to promote sputum discharge at the same time, also play a certain cough, asthma effect. Bronchospasm and mucosal edema mainly cause wheezing, but also cough due to increased stimulation of expiratory resistance: lumen obliteration caused by bronchial spasm aggravates the difficulty of expectoration. Therefore, antiasthmatic drugs also help cough