Nonionic contrast media (cm) are more and more widely employed in vascular radiology. These cm are the choice in some conventional arteriographies owing to their better tolerability. In intravenous digital subtraction angiography (DSA) the analysis of the personal material and of the literature allows to state that: the image quality with ionic and non ionic cm is similar; the tolerability of nonionic cm is slightly superior; the cardiac and renal toxicity of nonionic cm is slightly lower; reactions to nonionic cm take place with a lower frequency; the price of nonionic cm is considerably higher. Therefore nonionic cm seem to be slightly superior to ionic agents on the basis of these data and they should be theoretically preferred. The only doubt to their routine use in intravenous DSA is the high cost. Therefore we prefer to employ them in risk patients only, as ionic cm in current use are safe and cheap.