The effects of inhaling 0.4 mg of fenoterol hydrobromide (Berotec), 0.2 mg of albuterol (salbutamol), or placebo were compared in a double-blind three-way crossover study in a group of 12 asthmatic patients. After inhalation of fenoterol, the maximum increase in the forced expiratory volume in the first second (FEV1) was 0.76 L (48 percent) and in the peak expiratory flow (PEF) was 100 L/min (47 percent). The corresponding figures after inhalation of albuterol were 0.68 L (46 percent) and 98 L/min (48 percent), respectively. In comparison with administration of placebo, the FEV1 was significantly increased until six hours after inhalation of either drug. From three to six hours after inhalation, the effect of administration of fenoterol (as measured by FEV1 or PEF) significantly exceeded that of albuterol. Administration of either drug resulted in approximately equal bronchodilation (as measured by the increase in FEV1 or PEF), the effect of inhalation of fenoterol being of longer duration.