20 patients from the above population with significant encephalopathy will be randomized to receive either rifaximin or placebo. Post-treatment evaluation for severity of hepatic encephalopathy and breath test analysis for bacterial overgrowth will then be performed. The effect of treatment on changes in hepatic encephalopathy and bacterial overgrowth and the relationship between changes in bacterial overgrowth and severity of hepatic encephalopathy will also be assessed.