Iohexol, a new non-ionic water-soluble contrast medium, was tested for digital intravenous angiography of the cervical and intracranial vessels. In a double blind study involving 40 adult patients, iohexol and meglumine-Na diatrizoate were compared for safety, patient tolerance, and radiographic image quality. Iohexol was shown to be safe and generally produced less patient discomfort, leading to a lower incidence of motion, swallowing or cough artifacts.