We did 2 consecutive randomized studies to compare the effects of diatrizoate, ioxaglate, and iohexol. Sixty patients were studied: 15 with diatrizoate (group I) versus 15 with ioxaglate (IIA), and 15 with ioxaglate (IIB) versus 15 with iohexol (III). Group I had hypotension and severe increase in end-diastolic pressure. Severe bradycardia was seen in 27% of the cases. Group IIA and IIB had identical changes, with a moderate increase in systolic and end-diastolic pressure. Group III only presented a mild increase in end-diastolic pressure. None of the low-osmolar contrast media produced severe bradycardia, but ioxaglate induced frequent (20%) nausea. Our results suggest the best contrast media for angiocardiography is, in decreasing order: iohexol, ioxaglate, and diatrizoate.