This study prospectively examined the pharmacologic treatment of all wheezing children presenting to a pediatric emergency department from December 1987 to September 1991 (10,091 cases). There were increasing trends in rate of hospitalization, use of oxygen saturation measurements, use of corticosteroids and beta agents at discharge, and use of aerosolized bronchodilators administered in the emergency department. This cohort shows decreasing trends in use of theophylline and the use of subcutaneous bronchodilators administered in the emergency department. Increasing patient severity could not be confirmed in this cohort. The increase in use of corticosteroids in wheezing children is well supported in the literature. The use of theophylline appears to have significantly declined while there is still some controversy over its recommendations in the literature.