The systemic, pulmonary and renal haemodynamic effects following an intravenous infusion (1 ml/s, 4 ml/kg) of a non-ionic iso-osmolar contrast medium (iodixanol) were investigated in 8 pigs. Histopathologic changes occurring after infusion of iodixanol were studied by repeated renal biopsies. Iodixanol caused a significant increase of cardiac output, mean right atrial pressure, mean pulmonary arterial pressure, mean pulmonary arterial occlusion pressure and mean arterial pressure. There was a decrease of the systemic and pulmonary vascular resistances. Most renal biopsies showed no pathologic findings after infusion of iodixanol but in 3 specimens proteinaceous content was observed 15 min after infusion.