The management of the young asthmatic child is still controversial and it has been questioned whether the infant and very young child with asthma respond to beta 2 agonists. We studied the response to nebulized beta 2 agonists in 43 children under the age of 2 years who presented to the emergency room with acute asthma. Clinical score and oxygen saturation were determined on admission to the emergency room and at least 30 minutes after each inhalation. The clinical score was defined as the sum of five variables (heart rate, respiratory rate, dyspnea, accessory muscle use, and wheezing), each graded as 0 or 1. The mean clinical score improved significantly after nebulized albuterol (mean +/- SD, 3.75 +/- 1.2 versus 2.80 +/- 1.65, P less than .01). Mean oxygen saturation did not change significantly (mean +/- SD, 94.8% +/- 2.85 versus 95.2% +/- 2.54). Only three patients had a decrease in arterial oxygen saturation of greater than 2% (3% in each one of them) following bronchodilator therapy. Our results suggest beta 2 inhalation to be beneficial to the majority of asthmatic children younger than 2 years of age and safe to administer. The combination of clinical score and oxygen saturation provides a simple noninvasive method of monitoring the response to therapy in young children with acute asthma.