Abstract: The suspension of 2,4,6, -triiodo-3-acetamidobenzoic acid(N-cyclohexyl carbamyloxy) ethyl ester (TABAC) is a new hepatosplenography agent which is administered intra-venously. The pharmacokinetics of the ¹³¹Ⅰ labeled TABAC suspension was investigated in rats.After the suspension was given intravenously to rats, the blood radioactivity level decreased very rapidly followed by a slow decreasing period. It showed the characteristics of two biological phases, the distribution phase and the elimination phase. According to the shape of blood level curve, 2-compartment open model could be fitted and the kinetic expression of blood level curve could be described byC=5.51 e^-0.0583t+0.245 e^-0.00221t The liver radioactivity level of the drug after intravenous administration to rats rose very rapidly, and an absorption peak appeared in 45 minutes after injection. The kinetic expression of liver drug-time curve could be described byC=55.5e^-0.00125t+27.0e^-0.0171t-77. 0e^-0.151t The distribution studies of the drug in different organs after i.v. administration to rats showed that the highest radioactive level was found in the liver and it approximated 70% of the total administered dose. In comparison with liver, the radioactivity in spleen, lungs, heart and kidneys was found to be relatively lower.Up to 96 hours after injection about 44.7% of the administered radioactivity were excreted in the urine, while about 26.7% were found in feces.