Two groups of patients with minimal hepatic encephalopathy will be studied. The treatment group (n=17) will receive whole milk (24 g lactose) and the control group (n=17) will receive "lactose-free" milk (3.5 g of lactose) two times a day for 21 days. Clinical history, nutritional assessment, biochemical studies, psychometric tests, critical flicker frequency and a quality of life questionnaire will be performed. The patient will be assessed weekly 21 days. An external monitor will control the randomization process in order to allocate the patients into both study group and will not share the assignation codes with anyone until the end of the study.