Patients with chronic obstructive pulmonary disease (COPD) often subjectively benefit from inhaled beta 2-agonists in spite of little or no demonstrable effect in forced expiratory volume in 1 second (FEV1.0). A comparison between the effects of terbutaline administered via a dry powder inhaler (Turbuhaler) and via a chlorofluorocarbon (CFC) inhaler in conjunction with a spacer device (Nebuhaler) was performed in patients with regard to FEV1.0, forced expiratory capacity (FVC), residual volume (RV), and specific conductance (s-Gaw). Fifteen hospitalised patients (11 male) with COPD were studied, each of whom had a diurnal variation in peak expiratory flow (PEF) not exceeding 15% and with a demonstrated volume response to inhaled beta 2-agonists in FVC and/or RV of at least 15%. Patients were administered each of the following five treatments on a single occasion in a randomized order (latin square) in intervals of at least 2 days: placebo, terbutaline via Turbuhaler (1.0 and 2.5 mg) and terbutaline via a CFC inhaler (1.0 mg without and 2.5 mg with Nebuhaler). Inhalation of terbutaline in different doses and from different devices induced a decrease in RV, an increase in FVC, and s-Gaw and a less pronounced increase in FEV1.0. No statistically significant differences between the four terbutaline treatments were seen, but all were significantly different from the placebo. These findings indicate that while patients with COPD may benefit from inhaled terbutaline through decreased hyperinflation, the choice of inhalation device seems to be of little importance for its efficacy.