To test the hypothesis that early parenteral corticosteroid administration may be associated with a rapid improvement in airflow obstruction in adult asthmatic patients, a randomized, double-blind placebo-controlled study was carried out. Forty-five adult asthmatic patients, with initial peak expiratory flow rates (PEFRs) of < 200 L/sec received an intravenous bolus of either 125 mg methylprednisolone (MP) or normal saline before any other emergency department treatments. This was immediately followed by 3 aerosol treatments of 2.5 mg of albuterol separated by 20-minute intervals. PEFRs and heart rates were measured over a 1-hour time frame. There was not a significantly higher rate of increase of PEFR in the MP group compared with the saline group. Similarly, the rate of increase in percent PEFR showed a trend to being higher in the saline group (P = .061). There was no significant difference in the proportion of hospitalizations and side effects between the two groups. Adjustment for other variables did not result in a model showing an enhanced PEFR improvement with MP treatment. This study does not support the concept that corticosteroid treatment effects are beneficial within the first hour after administration. Further studies of rapid-acting modalities to enhance bronchodilation are needed in treating acute asthmatics.