目的　通过吸一支烟研究香烟烟雾直接作用于呼吸道后 ,气道所产生的反应。方法　以气道高反应性(BHR)测定仪 ,对吸烟者进行吸烟前后的气道即刻反应测定。结果　吸烟后气道反应性增高 ,通气不畅 (P <0 0 5 ) ,并随吸烟指数的增加气道受损加重 (P <0 0 1)。结论　吸烟对呼吸道起着直接的损害作用 ,也是引发急、慢性支气管炎及阻塞性肺气肿的重要原因之一 Aim To study the responses of the airways by smoking a cigarette to study the direct effects of cigarette smoke on the respiratory tract. Methods The airway hyperresponsiveness (BHR) detector was used to measure the immediate airway response of smokers before and after smoking. Results After the cigarette smoking, the airway reactivity was increased, the ventilation was poor (P <0.05), and the airway damage was aggravated with the increase of smoking index (P <0.01). Conclusion Smoking plays a direct role in damaging the respiratory tract and is also one of the important causes of acute and chronic bronchitis and obstructive pulmonary emphysema