The use of steroids in treating acute respiratory obstruction is still controversial. In this double-blind controlled trial, we decided to examine the beneficial effects of a single large dose of methylprednisolone (MSSP), using objective criteria. In the emergency setting, methylprednisolone (30 mg/kg) has been shown to decrease the need for hospital admission in patients with acute bronchospasm. No difference in this improvement was seen among patients in the steroid-dependent or non-steroid-dependent populations. Based on our findings, we suggest that the early use of single-dose steroid therapy is appropriate treatment for patients with acute bronchospastic attacks.