Although the inhalation of beta2-agonists has frequently been used to relieve acute asthma attacks, the efficacy of anticholinergic agents for acute asthma attacks still remains unclear. This study was designed to compare the inhalation of fenoterol and the inhalation of fenoterol plus oxitropium bromide delivered by a metered-dose inhaler with holding chamber (InspirEase) to relieve acute asthma attacks. To accomplish this, 69 patients who had presented with an acute asthma attack were randomized to receive either fenoterol (1 puff [200 microg/puff] every 1 min for 5 min; total 1000 microg) or fenoterol plus oxitropium bromide (2 puffs [100 microg/puff] every 1 min for 5 min; total 1000 microg). The peak expiratory flow (PEF) and forced expiratory volume in 1 sec (FEV1) values were measured before treatment, and 1, 15, 30, and 60 min after the inhalation therapy. The ratios of improvement, PEF (or FEV1) after treatment divided by PEF (or FEV1) before treatment, were also calculated. Thirty-three patients were evaluated in the combination group and 31 patients were evaluated in the fenoterol group. The PEF value at 60 min after inhalation therapy of the fenoterol plus oxitropium bromide group (261 +/- 18 L/min, mean +/- standard error) was significantly higher compared to that of the fenoterol group (210 +/- 17 L/min). In addition, the ratios of improvement of PEF at 1, 15, 30, and 60 min after inhalation therapy were significantly higher in the fenoterol plus oxitropium bromide group compared with the fenoterol group.