Dopamine is known to increase cardiac output and, to a greater extent, renal blood flow. The purpose of this study was to find out whether renal blood flow is increased partly at the expense of splanchnic blood flow. The splanchnic blood flow was evaluated by measuring, according to Fick's principle, the estimated liver blood flow during a continuous infusion of indocyanine green. Each determination was coupled with a measurement of the cardiac output, using a thermodilution method. The results were corrected to body surface, thus providing a cardiac index (Cl) and a hepatic index (Hl). The study involved 10 subjects free from hepatic, haemodynamic or haemorrhagic disease and was carried out in 3 stages: determination of initial values, then of values under dopamine (10-12 micrograms. kg. min) and finally, control of return to initial levels. The results showed that dopamine produced a significant (p less than 0,01) increase in Cl (mean 44%) and an equally significant (p less than 0,01) increase in Hl (mean 66%), the difference between the two increases being also significant (p less than 0.05). There was a strong correlation between Cl and Hl during dopamine fusion.