The new short-acting steroid muscle relaxant Org NC 45 was tested clinically in 18 patients and compared with a similar application of pancuronium bromide in 22 patients. Onset, duration and slope of recovery were significantly shorter for Org NC 45. No cumulative effects were noticed over several consecutive doses of Org NC 45. No tachycardia or arterial pressure changes were noticed with doses of Org NC 45 up to 130 μg kg −1 which was three times the 95% blocking dose.