The study will be performed on 50 patients with cirrhosis and chronic hepatic encephalopathy [25 Rifaximin and 25 placebo] aged between 18 and 75 years managed within the Liver Unit at King's College Hospital which is the largest tertiary Liver Transplant Centre within the UK. For the purposes of this study a patient will be considered to have cirrhosis if they fulfil 2 out of 3 diagnostic criteria of confirmatory liver histology, biochemistry and/or radiologic findings consistent with cirrhosis/portal hypertension, and are presenting with chronic persistent overt hepatic encephalopathy (≥ grade 1) or with ≥2 episodes of overt hepatic encephalopathy in the previous 6 months.