Objective：To investigate the protective effects and mechanisms of total flavonoids（TF） on α-naphthylisothiocyanate-in－duced（ANIT-induced） cholestatic liver injury in mice. Methods：Sixty Kunming mice were evenly randomized into 6 groups，namely normal group，model group，biphenyl dimethylester group（0.15 g/kg），high-dose，middle-dose，and low-dose TF groups（1.2，0.6，0.3 g/kg）. Except for the blank control group，the acute liver injury model was established by intraperitoneal injection of ANIT，and went gastric lavage with total flavonoids extracted from Polygonum knotweed L. for 9 consecutive days. After fasting for 20 hours，the liver tissue and the blood from eyeballs were taken out，and the content of SOD，MDA and GSH in liver tissue，as well as the serum level of ALT，AST，LDH，TBA，TBIL were measured. Results：Compared with the model group

Serum ALT levels in high dose group mice of total flavonoids extracted from Polygonum knotweed L[（243.14±27.35） U/L]，Levels of AST[（345.02±24.01） U/L]，Levels of LDH[（505.97±68.56） U/L]，TBA[（112.02±17.16） nmol/mL]，TBIL[（15.08±4.09） nmol/mL] and GSH contents in the liver[（63.08±4.88） ?滋mol/mg] as well as MDA contents[（3.55±0.32） nmol/mg] were lower in high-dose TF group than in model group，The differ－ence was statistically significant（P<0.05）. Serum ALT levels in medium dose group mice[（330.56±24.74） U/L]，levels of AST [（438.60±32.51） U/L]，LDH[（597.90±66.90） U/L]，TBA[（144.62±16.37） nmol/mL]，TBIL[（27.36±6.51） nmol/mL] and GSH con－tents in the liver[（54.52±3.80） ?滋mol/mg] as well as MDA content[（5.65±0.35） nmol/mg] were also lower in middle-dose TF group than in model group

the difference was also statistically significant（P<0.05）. Conclusion：The total flavonoids extracted from P. knotweed exerts therapeutic effect on ANIT-induced liver in－jury with cholestasis in mice.