OBJECTIVE： To study the protective effects of different parts （fruit pulp， fruit core， whole fruit） extracts of Cornus officinalis on acetaminophen-induced acute liver injury in mice， and to provide reference for its complete development and utilization. METHODS： Totally 120 mice were randomly divided into normal control group （normal saline）， model group （normal saline）， bifendate group （positive control， 150 mg/kg）， low-dose， medium-dose and high-dose groups （1.56， 6.24， 12.48 g/kg， calculated by crude drug） of C. officinalis fruit pulp， fruit core， whole fruit extracts， with 10 mice in each group. They were given relevant medicine intragastrically once a day for consecutive 7 d. 6 h after last medication， normal control group was given normal saline intraperitoneally， and other groups were given acetaminophen 300 mg/kg intraperitoneally to induce liver injury model. 16 h after modeling， the levels of ALT， AST and MDA in serum as well as the levels of GSH-Px and SOD in liver tissue were determined. HE staining was used to observe the pathological changes of liver tissue in mice. RESULTS： Compared with normal control group， the serum levels of ALT， AST and MDA in model group were increased significantly （P＜0.01）， while the levels of SOD and GSH-Px in liver tissue were decreased significantly （P＜0.01）； the inflammatory cell infiltration was observed in the liver tissue of the model group， accompanied by hepatocyte degeneration and flaky necrosis. Compared with model group， the serum levels of ALT， AST and MDA in C. officinalis fruit pulp extracts medium-dose group as well as the serum levels of ALT and MDA in C. officinalis fruit pulp extracts high-dose group were decreased significantly （P＜0.05 or P＜0.01）. Serum level of MDA in C. officinalis fruit core extracts low-dose group， the serum levels of ALT and AST in C. officinalis fruit core extracts medium-dose and high-dose groups were decreased significantly （P＜0.05 or P＜0.01）. The serum levels of ALT and AST were decreased significantly in C. officinalis fruit extracts medium-dose and high-dose groups （P＜0.05 or P＜0.01）. The necrosis of liver cells was relieved in different parts of extracts C. officinalis middle-dose and high-dose groups to different extent. The structure of liver lobule was basically intact， and no necrosis of liver cells was observed in C. officinalis fruit core medium-dose and high-dose groups， C. officinalis fruit extracts high-dose group. CONCLUSIONS： Different parts extracts of C. officinalis have protective effects against acetaminophen-induced acute liver injury model mice， and the effect of C. officinalis fruit core extracts is similar to that of C. officinalis fruit extracts. The mechanism of hepatoprotection may be related to anti-oxidative stress reaction.