Cryptotanshinone (CT), isolated from the dried roots of Salvia militorrhiza , has been reported to have protective effects on myocardial and cerebral ischemia/reperfusion (I/R) injury both in vitro and in vivo . However, its effects and underlying mechanism on hepatic I/R injury remain unclear. To investigate its effects on hepatic I/R injury, thirty male Sprague-Dawley rats were randomized into 3 groups: a sham group, a vehicle-treated hepatic I/R group and a CT-treated (50 mg/kg) group. The hepatic I/R and CT-treated groups were subjected to 60 min of normothermic ischemia of the left lateral lobe of the liver, followed by 4 h of reperfusion. The animals were then sacrificed to collect the serum and the left liver lobe for assay. Hepatic function was protected, as evidenced by significantly reduced alanine aminotransferase (ALT), aspartate aminotransferase (AST) and malondialdehyde (MDA) levels in the CT-treated group as compared with I/R group. The terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) demonstrated significantly decreased apoptosis in the CT-administration animals. Western blotting demonstrated upregulation of the proapoptotic protein Bcl-2, as well as decreased levels of the activated form of caspase-3 and the cleaved form of its substrate, poly(ADP-ribose) polymerase (PARP) in the CT-treated group compared with those of the I/R group. In addition, the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinases (MAPKs) was inhibited by CT. Our data suggest that CT attenuates hepatic I/R injury by inhibiting the intrinsic pathway of apoptosis, mediated partly through the inhibition of JNK and p38 MAPK phosporylation.