A 38-year-old woman developed acute, severe weakness during the treatment of status asthmaticus that included high-dose intravenous corticosteroids. A muscle biopsy and EMG indicated a myopathy, and nerve conduction studies disclosed a neuropathic component. In association with corticosteroid tapering, the clinical, EMG, and nerve conduction abnormalities resolved. In some patients, intensive treatment of status asthmaticus may cause a reversible, toxic disorder of muscle and nerve.