The bronchodilating response to two doses of 100 micrograms of salbutamol introduced into an extension device (Aero-chamber [AC]), each followed by four tidal breaths, was compared with the nebulization of 2.5 mg of salbutamol in a saline solution during tidal breathing in a crossover study of ten patients with reversible airway obstruction. The forced expiratory volume in one second (FEV1) and the forced vital capacity 30 min after the drug administration improved significantly with both methods (p less than .001). The improvement of FEV1 with the AC (52.1 percent) compared with the nebulization (55.7 percent) was similar (p greater than .05).