The aim of the study was to analyze the bronchodilator test (BDT) response to ipratropium bromide (IB) in patients with chronic obstructive pulmonary disease (COPD) who do not respond to inhaled terbutaline. Sixty patients with stable COPD who showed a negative response to BDT, defined as an increase of less than 160 ml in the forced expiratory volume in the first second (FEV1) after inhaling 1500 microg of terbutaline, were recruited. Each patients randomly received 200 microg of IB or placebo in a single blinded fashion, and a spirometric study was made at 30 and 60 min. The increase in absolute values of FEV1 at 30 and 60 min after IB was significantly higher than after placebo. The means +/- SD were 126 +/- 93 vs. 70 +/- 96 ml at 30 min and 148 +/- 120 vs. 74 +/- 132 ml at 60 min (P=0.01). The BDT was positive in 57% of patients who received IB, considering a positive response as an increase of FEV1 greater than 160 ml (P=0.01). We conclude that the BDT was positive with high doses of IB in more than half of COPD patients who did not respond to terbutaline alone.