Low-dose Rifaximin in the Treatment of Covert Hepatic Encephalopathy

Inclusion Criteria: 1. Patients agreed to sign the informed consents 2. Patients aged 18-70 years，males or females 3. Patients who were diagnosed with occult hepatic encephalopathy by PHES and Stroop tests Exclusion Criteria: 1. Allergy to rifamycin/rifamutin/rifampin/rifapentine 2. Current or recent (\<3 month) use of alcohol or can't stop drinking during the study period 3. Use of antibiotics within last 6 weeks 4. Use of lactulose/lactitol, probiotics, L-ornithine-L-aspart，zinc，metronidazole, neomycin, or rifaximin within last 6 weeks 5. Infection or gastrointestinal hemorrhage within last 6 weeks 6. Use of psychoactive drugs within last 6 weeks 7. Occurred overt hepatic encephalopathy within last 3 months 8. history of portosystemic shunt surgery or transjugular intrahepatic portosystemic shunt 9. Poor vision, color blindness or motor defects that interfere with the performance of psychometric tests 10. Other non-controllable neurological or psychiatric problems which may affect cognitive function such as Alzheimer's disease, Parkinson's disease or schizophrenia 11. Conformed or highly suspicious diagnosis of liver malignant tumors 12. Human immunodeficiency virus (HIV) infection 13. Uncontrolled hypertension, diabetes or other serious cardiac and pulmonary diseases 14. White blood cell count\<1×10\^9/L 15. Pregnancy and breastfeeding 16. Participated in other drug clinical trials within 3 months 17. The researchers thought it was not suitable for this clinical trial