We tested the relative efficacy of bronchodilators delivered in aerosol and in oral form in 17 patients with asthma in a double-blind randomized sequence. Treatment consisted of a 20-mg tablet of metaproterenol sulfate, five puffs of metaproterenol aerosol (0.65 mg in each puff for a total of 3.25 mg) administered 20 minutes apart between puffs, a combination of both, and placebos. Bronchodilator response measured by forced expiratory volume in 1 second (FEV1) was significantly greater on the aerosol and the combined regimen than on the oral and placebo regimen. The combined regimen produced a greater bronchodilator response than the aerosol alone, but the difference was not significant. Side effects were frequent after oral medication but absent after the aerosol. Sequential inhalation of aerosol is the preferred route of administration of adrenergic bronchodilator drugs in asthma.