The kinetics of 99mTc-Trimethyl-Br-IDA blood clearance was analysed in the rat 24 h after warm ischaemia and reperfusion of the liver. There were changes in the elimination of 99mTc-Trimethyl-Br-IDA depending on the length of the ischaemic period and the dose given. Statistically significant differences were found between the various periods of ischaemia when higher doses of the radionuclide were utilised. At lower doses, the clearance was not capable to discriminate between control rats and rats submitted to 45 min of ischaemia, but it did discriminate more severe degrees of ischaemic liver injury. Instead, galactose elimination capacity discriminated between ischaemic and control rats, but not between 45 and 90 min or between 90 and 120 min of ischaemia. Alanine aminotransferase was able to discriminate between control and ischaemic rats and between 45 and 90 min of ischaemia, but not between 90 and 120 min of ischaemia. The response of 99mTc-Trimethyl-Br-IDA clearance under extreme conditions of ischaemia and reperfusion is consistent and opens a possible window for the application of this test in the quantification of liver function in severely damaged livers and in decision making and prognosis in liver disease.