Objective To explore possible mechanism of Dahuang Decoction in treating minimal hepatic encephalopathy（MHE）.Methods Randomly divided 29 cases of patients with MHE into the Dahuang Decoction group（15 cases） and the placebo group（14 cases） The Dahuang Decoction group was given Dahuang Decoction 200 ml for retention enema.The placebo group was given sterile water injection 200 ml for retention enema.Both once per day

lasted for 7 days as a course.Examined metabolite in serum samples before and after treatment.Analyzed changes of metabolite in serum samples of patients before and after treatment using principal component analysis（PCA） and partial least square discrimination analysis（OPLS-DA）.Results PCA indicated that grouping trend of serum metabolite profile of the placebo group and the Dahuang Decoction group before and after treatment was not obvious and had much overlap.Model parameter R X was respectively 0.393 and 0.509.Model interpretability was not good enough.OPLS-DA showed that model parameter of the Dahuang Decoction group R

2

X = 0.280

R

2

Y = 0.954

Q

2

Y =-0.097;Model parameter of the placebo group R

2

X =0.397

R

2

Y =0.941

Q

2

Y =-0.605.The model was not established successfully.Serum metabolite profiling of patients with MHE in two groups before and after treatment had no obvious difference.Conclusion Dahuang Decoction has no obvious effect on serum metabolite profiling of patients with MHE.