Increased intestinal permeability has for many years been implicated as a possible contributory factor in the development of encephalopathy and spontaneous bacterial peritonitis (SBP) seen in patients with cirrhosis. The majority of studies indicate that there is an increase in small intestinal permeability in cirrhotic patients and there is also evidence of an increase in patients with acute liver failure. The cause of these changes is unknown and whether they are related to the development of SBP and encephalopathy is unclear.