Minimal hepatic encephalopathy (MHE) is present in 30 to 84% of patients with liver cirrhosis. 531 patients with liver cirrhosis were treated in our department within 12 months and, based on clinical tests +/- hyperammonemia, 16,4 % ( n= 87) of these patients suffered from manifest hepatic encephalopathy. HE significantly affects neurocognitive functions leading to impaired quality of life, already if present in subclinical stages. Diagnosis of MHE is established by psychometric tests (e.g. number connection test, figure connection test, picture completion test). Objective and sensitive methods to assess MHE are visual evoked potentials and critical flicker frequency analysis (CFF). A continuous therapy with rifaximin in combination with Lactulose significantly reduces the risk of overt HE, recurrence and HE-related hospitalisations in randomized double-blind placebo-controlled clinical trials . A therapy with Lactulose has been shown to improve cognitive functions . Rifaximin is a minimally absorbed gut-selective antibiotic and thus impacts on gut microbiome. The role of the gut microbiome in the pathophyiology of hepatic encephalopathy is still little understood.