The aim of this study was to examine the acute effect of tobacco smoke exposure and inhaled terbutaline on mucociliary clearance in 9 healthy smokers. It was based on a recently described method for scintigraphic visualization of the bronchi (bronchoscintigraphy). After an initial bronchoscintigram had been made by having the subjects inhale aerosolized 99mTc-albumin, they inhaled either terbutaline or placebo from a metered-dose inhaler. Subsequently, data acquisition for production of bronchoscintigrams was repeated at 10 min intervals for 120 min, and the mucociliary clearance was estimated from the movement of radioactivity in the series of bronchoscintigrams thus obtained. On two study days the subjects remained tobacco abstinent, while on two occasions they chain-smoked during the examination. Acute tobacco exposure resulted in an increased clearance rate in the lobar bronchi in 8 of the 9 smokers (p less than 0.03), while in the main bronchi and the trachea the effect was inconsistent. In all subjects terbutaline systematically increased the clearance rate in all visible bronchial structures compared to placebo (p less than 0.04). The combination of smoking and terbutaline caused a faster clearance rate in the lobar bronchi in most subjects than tobacco smoke or terbutaline alone. It is concluded that both acute tobacco exposure and terbutaline increase mucociliary clearance in healthy smokers.