We have investigated the ability of 99Tcm-disofenin (DISIDA) kinetics to measure liver function. Two approaches have been used: first, quantitative analysis of serial liver images, and second, clearance estimation from whole blood concentration-time data. Graded liver dysfunction was produced in 11 dogs over three months by common bile duct ligation and surgical relief of biliary obstruction one month later. The kinetic analysis of serial liver images showed clear abnormalities during biliary obstruction, with calculated rates of liver uptake falling in stages from 11.09 to 5.15 cts s-1 (p less than 0.001), and rates of elimination from the liver from 8.8 to 1.6 x 10(-4) cts s-1 (p less than 0.0001). These parameters paralleled the deterioration and recovery of liver function through the experimental period, and had not fully recovered 7 weeks after relief of biliary obstruction (10.5 and 6.2 x 10(-4) cts s-1 respectively). Serial blood sampling after injection of DISIDA permitted calculation of whole blood disposition rates (for hepatic clearance). Mean values fell from 256 to 67 ml min-1 with chronic biliary obstruction (p less than 0.001), and returned to almost normal (206 ml min-1) 10 days after surgical relief of biliary obstruction. It is clear that the gradual nature of recovering liver function was more sensitively identified by image analysis than serial blood data. Serial liver biopsies showed marked changes following biliary obstruction. These improved over a period of 7 weeks following its relief, when there was still considerable residual abnormality. This work supports the view that hepatic abnormalities caused by biliary obstruction do not recover quickly following its relief. DISIDA kinetics can quantitate both major and minor degrees of hepatic dysfunction, and may prove to be a valuable method to quantitative liver function.