The complications of cerebral angiography have been recorded in 1509 examinations with metrizoate (Isopaque Cerebral) and in 1000 examinations with iohexol (Omnipaque). The frequency of complications was 2.0 percent for metrizoate and 1.3 percent for iohexol. Permanent sequelae were seen in 4 patients, 3 in the metrizoate and one in the iohexol group. One of these patients died, probably from thromboembolism. Blood coagulation parameters were studied during the angiography in 22 patients and only minor, probably clinically insignificant changes were found, with no difference between the two contrast media.