Hepatic encephalopathy is caused by the effects on the brain of substances that under normal circumstances are efficiently metabolized in the liver. The hyperammonemia is the main factor responsible for the development of hepatic encephalopathy. In patients with cirrhosis, the reduction in hepatocellular function and generation of portosystemic shunts contribute to increase serum ammonium. The current therapeutic approaches, are aimed at reducing blood ammonium levels.