It was reported that pentoxifylline(PTX) improved tissue oxygenation and increased survival rate in animal models of hemorrhagic shock. The authors investigated the salutary effects of PTX on hemodynamics, oxygen transport and tissue metabolism in animal models of hemorrhagic shock. 18 anesthetized cats were subjected to hemorrhage to MABP of 40-45 mmHg and this pressure was maintained for 120 minutes. After this period, normal saline was administered in a volume double the original shed blood volume over 30 minutes. Thereafter the cats were observed for 120 minutes. Drug-treated cats received at 25 mg/kg i.v. bolus of PTX at the beginning of hemorrhage, followed by a continuous infusion of 25 mg/kg/hr throughout the experiment. PTX had no effect on MABP, pH(a-cv), P(cv-a) CO2 and lactic acid value but, PTX group had more rapid HR and higher PcvO, than placebo group(P<0.05). In addition, we found that pH(a-cv) and P(cv-a) CO2 changes occurred more rapidly than lactic acid changes(P<0.05) after hemorrhagic shock. So, pH(a-cv) and P(cv-a) CO2 changes might be considered as useful parameters for early detection of derangement of tissue oxygenation in shock states. It was concluded that PTX had no effects on indices of representing tissue oxygenation except improvement of central venous oxygen tension in this feline hemorrhagic shock model. Further studies are needed.