Objective To observe the clinical effects of ornithine aspartate (OA) and lactulose on the prevention and treatment of hepatic encephalopathy for patients with portal hypertension after modified transjugular intrahepatic portosystemic shunt (TIPS).Methods Fifty-six patients with portal hypertension were treated by modified TIPS,OA and lactulose after the operation were given,the incidence of postoperative hepatic encephalopathy and the changes of blood ammonia were observed.Patients with hepatic encephalopathy after modified TIPS accepted therapeutic dosage of OA and lactulose,and the clinical effects of combined OA and lactulose on treatment of the hepatic encephalopathy after modified TIPS and changs of blood ammonia were evaluated as well.Results Prophylactic use of combined OA and lactulose after modified TIPS,there was no hepatic encephalopathy happened in 56 patients.Hepatic encephalopathy was seen in 5 patients after discontinuation of combined OA and lactulose,the incidence rate of hepatic encephalopathy was 8.93％ (5/56).The level of blood ammonia in patients after modified TIPS was significanby higher than that before treatment [(88.2 ± 23.0) μ mol/L vs.(43.1 ± 19.2) μ mol/L,P ＜ 0.05].Five patients with hepatic encephalopathy was improved quickly after given therapeutic dosage of OA and lactulose (the average treatment time was 7 d),and the level of blood ammonia was significantly lower than before treatment [(69.1 ± 14.1) p mol/L vs.(139.2 ± 15.8) μ mol/L,P＜ 0.05].Conclusion Combined OA and lactulose can effectively prevent and treat the hepatic encephalopathy after modified TIPS,its mechanism may be associated with reduction of blood ammonia level.