Thirty-two 5- to 17-year-old children who had severe, acute asthma were randomly assigned to receive either high doses (0.15 mg/kg of body weight per dose) or low doses (0.05 mg/kg of body weight per dose) of nebulized albuterol every 20 minutes for six doses. Compared with the low-dose regimen, the high-dose regimen resulted in significantly greater improvement in forced expiratory volume in 1 second, forced vital capacity, and wheeze score and a lower hospitalization rate. The changes in heart rate, respiratory rate, blood pressure, white blood cell count, and serum potassium concentration did not differ significantly between the groups. The incidence of side effects, which included tremor, hyperactivity, and vomiting, was not significantly different in the two populations. Serum albuterol levels varied widely, but there was no correlation between the levels and the increase in heart rate or other side effects. high-dose, frequently administered, nebulized albuterol appears both safe and effective in treating severe, acute asthma in children.