A double-blind randomized, clinical trial was conducted in 9 hospitals comparing the use of non-ionic contrast media (CM) iopromide 300 (Ultravist) and iohexol 300 (Omnipaque) during peripheral arteriography in a total of 446 patients. After premedication with morphine-scopolamine each patient was given two consecutive injections of 50 ml CM at a rate of 12 ml/s above the aortic bifurcation. Both CM were well tolerated. There were no differences between the two substances as far as general tolerance, pulse rate, blood pressure, sensation of heat or pain after CM injection were concerned.