Minimal hepatic encephalopathy (MHE) is defined by the presence of neurophysiological alterations,with an important impact in the quality of life, in the risk of performing dangerous tasks as leading cars and heavy machinery and increases risk of overt hepatic encephalopathy. MHE is present in a third of cirrhotic depending on liver function. Psychometric and neurophysiologic test are used in the diagnosis of MHE, mainly PHES (Psychometric Hepatic Encephalopathy Score) battery, electroencephalogram, evoked potentials and measurement of the critical flicker frequency. Oral glutamine challenge (OGC) measures intestinal ammonia production after glutamine intake and indirectly intestinal glutaminase activity. Altered OGC in patients with MHE predicts short-time survival. In conclusion,MHE is the first stage in HE syndrome, affect to a third of cirrhotic and worsen quality of life. There are useful and easy-to-use diagnostic tests and new therapeutic options are warranted.