1. A method is described for the measurement of liver blood flow without hepatic venous catheterization by the injection of a single dose of bromosulphthalein and the analysis of the graph of the plasma disappearance of the indicator.
2. The rationale of the method was tested in three systems which covered a wide range of flow rates. The first system was a physical model with a haemodialyser in which the calculated flow could be compared with the flow measured directly. The second was in anaesthetized dogs, in which the calculated flow was compared with that measured by continuous infusion and hepatic venous catheterization, based on the Fick principle. The third system was in unanaesthetized turkeys, in which metabolism of bromosulphthalein does not occur. The calculated flow was compared with the flow measured simultaneously by the uptake of colloidal particles by the Kupffer cells.
3. In all three systems the correspondence between the two methods of measuring liver blood flow was good, the differences between them being not statistically significant.
4. The method has been applied to measurements of liver blood flow in man and animals and gives results comparable with those reported by other workers.