The bronchodilating effect of terbutaline dry powder inhaled via Turbuhaler was compared with terbutaline inhaled via a conventional, chlorofluorocarbon (CFC) inhaler and Nebuhaler (750 ml spacer) in 68 consecutive patients attending the emergency department with acute severe bronchial obstruction. The study was of an open, randomized, parallel group design with one study day. Patients were treated with 2.5 mg of terbutaline 15 min apart, either as dry powder via Turbuhaler or with a CFC inhaler in conjunction with Nebuhaler. Data from 62 patients were analyzed. The mean baseline FEV1 values were 0.81 L (SD, 0.64; range, 0.14 to 2.74 L) in the Turbuhaler group (n = 33), and 0.90 L (SD, 0.90; range, 0.27 to 2.60 L) in the Nebuhaler group (n = 29). The mean increases in FEV1 from baseline were 0.40 L (SD, 0.40; range, 0.06 to 2.36 L) and 0.21 L (SD, 0.25; range, -0.05 to 0.95 L) 10 min after the last inhalation via Turbuhaler and Nebuhaler, respectively. The difference between mean values of the increase in FEV1 after terbutaline treatment with Turbuhaler and the CFC inhaler and Nebuhaler was statistically significant (p = 0.0004, ANOVA). This study showed that inhalation of terbutaline via Turbuhaler produced a significantly greater increase in FEV1 compared with the same dose of terbutaline administered via the CFC inhaler and Nebuhaler in patients attending the emergency department with acute severe bronchial obstruction.