To evaluate the Modified Major Bupleurum Decoction’s effect on liver function and blood coagulation mechanism.Methods:A total of 50 rats were randomly divided into three groups:normal group (A group) with 10 rats,model group (B group) with 20 rats and Bupleurum Decoction group (C group) with 20 rats.C group were given 10 mL/(kg.d) oral Bupleurum Decoction 2 days before modeling.A and B group were given the same dose of 0.9%NaCl.B and C group rats were given subcutaneous injection of thioacetamide 0.2 g/kg per 24h for two days and then the acute liver failure models were established.For rats injected with thioacetamide for the first time,10%GS 0.25 g/kg were also administrated.After the model was established,Major Bupleurum Decoction lavage were given for three days,and A group rats were given the same dose of 0.9%NaCl.Three days later,all the rats were killed to take blood sample,and rats serum and tissue pathology were kept after 3 days.Pathological tissue,liver function indexes (ALT,AST,ALB,CHE),blood coagulation function indexes (PT) were compared among the three groups.Results:Compared with model group,the tissue of Major Bupleurum Decoction group was better; ALT,AST,TBiL of model group leveled up significantly compared with normal group rats(P<0.05),ALB and CHE of model group rats decreased significantly compared with normal group (P<0.05).Compared with model group,ALT,AST,TBiL of Major Bupleurum Decoction group decreased significantly(P<0.05),ALB、CHE of Major Bupleurum Decoction group increased significantly (P<0.05); PT of model group increased significantly compared with the normal group(P<0.05),PT of Major Bupleurum Decoction group decreased significantly compared with model group(P<0.05).Conclusion:Modified Major Bupleurum Decoction plays a protective role in liver function and blood coagulation mechanism.