Reports of corticosteroid sensitivity reactions are rare in the medical literature. We report an anaphylactoid reaction to hydrocortisone sodium succinate given intravenously which occurred on two occasions during treatment of a patient for asthma. Intradermal testing with a wide range of steroid preparations gave positive results with hydrocortisone sodium succinate, methylprednisolone sodium succinate, methylprednisolone sodium succinate and methylprednisolone acetate. No reactions occurred to dexamethasone sodium phosphate administered intravenously, prednisolone given orally or beclomethasone dipropionate by inhalation. Results of a radioallergosorbent test (RAST) were negative for hydrocortisone sodium succinate.