In a group of 48 patients with a renal cadaveric allograft 38 acute rejection episodes were treated by increasing the daily prednisolone doses to 300 mg the first day, 200 mg the second day and 100 mg the third day, gradually tapering down over a matter of weeks. In a second group of 48 patients 39 acute rejections were treated by 1 g of methylprednisolone intravenously on alternate days with a maximum of four injections. Rejection treatment was successful in 26 of 38 in the first group (68%) and in 30 of 38 in the second group (76%). Complications such as gastrointestinal bleeding, aseptic necrosis and diabetes were more frequent in the first series.