Patients with chronic bronchitis were randomly allocated to 4 weeks treatment with terbutaline 0.5 mg inhaled through a cone spacer with an expiratory resistance creating a positive expiratory pressure (+PEP group) or without (-PEP group). The patients recorded their symptoms in a diary and peak expiratory flow (PEFR) was measured before and after each inhalation. PEFR increased significantly after inhaled terbutaline both with and without PEP. The mean increase in PEFR after terbutaline inhalations was significantly greater (p less than 0.0001) in the +PEP group (24 L/min) compared to the -PEP group (17 L/min). The +PEP group had less sputum and less difficulty with coughing up sputum compared to the -PEP group. This study showed a small but significant enhancement of the bronchodilation and a beneficial effect on symptoms when inhalation of beta-2-agonist was combined with PEP in patients with chronic bronchitis.