The effects of methylprednisolone on the clinical fat embolism syndrome were studied in a series of 60 patients who had at least two fractures of the pelvis, femur and tibia and who did not have any other important injuries. This series was dichotomized at random, and 29 patients were given 10 milligrams per kilogram of methylprednisolone three times, once upon admission and, then, at eight and 16 hours post-traumatically. Thirty-one patients served as controls. Fat embolism syndrome was defined as a combination of hypoxemia, bilateral "snow storm" infiltrations of the lungs, petechial rash, mental disturbances, pyrexia, anemia and thrombocytopenia. Varying degrees of the syndrome were observed in two patients given methylprednisolone and in 15 patients in the control group. Methylprednisolone reduced all individual signs. There were no fatalities in this series of fracturers. No complications were observed from the use of methylprednisolone. Methylprednisolone in an early pharmacologic dosage is effective in fulminant instances of fat embolism that occur in spite of adequate respiratory care and the proper treatment of fractures.