Objective To evaluate the effect of live combined Bacillus subtilis and Enterococcus faecium enteric- coated capsules in the prevention and treatment of adverse events and complications after transcatheter arterial chemoembolization( TACE). Methods A total of 239 patients who were diagnosed with hepatocellular carcinoma and treated with TACE from January 2012 to December 2013 were randomly divided into experimental group( n = 111) and control group( n = 128). The patients in the experimental group were orally given live combined Bacillus subtilis and Enterococcus faecium enteric- coated capsules 3 days before surgery,and the patients in the control group were given placebo with the same appearance. The adverse events,incidence of complications,and blood ammonia level after TACE were compared between the two groups. Independent- samples t- test was performed for comparison of continuous data between the two groups,and chi- square test was performed for comparison of categorical data. Results Compared with those in the control group,the patients in the experimental group had a significantly lower incidence of adverse events such as pyrexia,abdominal distension,and constipation( t = 2. 728,2. 561,and 2. 026,respectively; all P < 0. 05); meanwhile,the patients in the experimental group had a significantly lower incidence of postoperative complications such as liver abscess,ileus,spontaneous bacterial peritonitis,and hepatic encephalopathy than those in the control group( t = 1. 969,2. 312,2. 987,and 2. 826,respectively; all P < 0. 05). After treatment,the patients in the experimental group had a significantly lower blood ammonia level compared with those in the control group( t = 1. 97; P < 0. 05). Conclusion As a new kind of live bacterial preparation,Bacillus subtilis and Enterococcus faecium enteric- coated capsules can reduce abdominal discomfort and blood ammonia level after TACE,as well as the incidence of severe complications including liver abscesses,but related mechanisms need further studies.