Twenty-five consecutive patients admitted with status asthmaticus were blindly randomized to receive intravenous (IV) methylprednisolone every six hours for three days at one of the following dosages: (1) low, 15 mg; (2) medium, 40 mg; or (3) high, 125 mg. All other therapy, including IV and inhaled bronchodilators, was kept constant. We measured forced expiratory volume in 1 s (FEV1) to quantitate response. The high-dose group improved significantly by the end of the first day, the medium-dose group improved by the middle of the second day, but the low-dose group did not improve significantly in three days. Together, the high- and medium-dose groups were significantly improved (FEV1 greater than 50% of predicted) compared with the low-dose group. No serious steroid side effects were encountered. We conclude that the greater benefit of higher doses of steroids, such as 125 mg of methylprednisolone every six hours, justifies their use in severe asthma.