Medication shortages pose serious problems in health care. This study examines the impact of a computer-based reminder in addressing a national methylprednisolone shortage. An alert was designed and implemented in a computerized order entry platform at a children's hospital. The alert informed physicians of the shortage and provided an alternative prescribing pathway. Data regarding the number and type of parenteral corticosteroid prescriptions were collected for a one-month period before and after the alert was implemented. The alert resulted in a 55% relative reduction in methylprednisolone use and an average reduction of more than three orders each day. Dexamethasone and hydrocortisone, the recommended alternative medications, increased in use by 12% and 49%, respectively. The alert resulted in a $36,552 annualized cost reduction to the institution. Similar alert applications have great potential for effectively altering physician prescribing behavior.