A dose-ranging, double-blind study of pulsed methylprednisolone in 71 patients with active classical or definite RA is reported. Single pulses of 40 mg, 500 mg or 1 g were administered during a 24-h admission. All patients benefited transiently, but only in those who received 1 g was this prolonged beyond 3 weeks. Laboratory measurements showed no significant change in any group. Significantly more patients in the 1 g group felt the treatment worthwhile than in the other groups. The drop-out rates in the 40 mg and 500 mg groups differed significantly from that seen in the 1 g group and were such that statistical analysis beyond 3 weeks was difficult to interpret. Side-effects were mild. Three patients subsequently developed avascular necrosis, one in the 1 g and two in the 40 mg groups. The study suggests that single doses of MP below 1 g are not helpful in the management of acute RA.