The role of heat shock pretreatment in the induction of tolerance for ischemia-reperfusion injury was investigated in rat livers with fibrosis produced by carbon tetrachloride (CCI4) injected subcutaneously. The control group (group C, n = 56) received no pretreatment except anesthesia, and the heat shock group (group HS, n = 56) were exposed to heat shock (42 degrees C) for 15 minutes. After a 48-hour recovery all rats were subjected to 30 minutes of warm ischemia. Western blotting analysis was employed for heat shock protein (HSP) 72 detection. The adenine nucleotide levels in liver tissue and the liver enzyme levels in serum were measured before and after ischemic intervention (seven animals were used at each of six time point measurements in both groups). HSP72 was induced in group HS at greater intensity than in group C. The survival rate on postoperative day 7 in group C (3/14) was significantly poorer than that in group HS (14/14) (p < 0.01). The higher survival rate in group HS was accompanied by more rapid recovery of the adenosine triphosphate level and lower serum levels of liver enzymes after reperfusion (p < 0.01 vs. group C). Heat shock preconditioning induces HSP72 in the rat liver with fibrosis and provides significantly increased tolerance of warm-ischemia reperfusion injury.