Objectives To evaluate gastrointestinal permeability in primary biliary cirrhosis (PBC), using a sensitive method to detect epithelial damage, and to correlate it with the Mayo score, histological stage, ascites, spontaneous bacterial peritonitis, endoscopic signs of portal hypertension and Helicobacter pylori infection. Methods Fifty consecutive patients with PBC and 39 patients with cirrhosis of other aetiologies (non-PBC) were enrolled in the study. Coeliac disease was initially ruled out in all participants. Permeability was assessed using sucrose (gastro-duodenum) and lactulose-mannitol (intestine). Results Sucrose excretion was above the limit in both PBC and non-PBC patients. Twenty-two per cent of PBC patients had an increased result for the lactulose-mannitol test compared to 12.8% of non-PBC cirrhotic patients. PBC patients had high sucrose excretion levels irrespective of the presence of any oesophageal varices, which significantly increased the gastroduodenal permeability in non-PBC patients only when associated with hypertensive gastropathy. Sucrose excretion was significantly enhanced by hypertensive gastropathy in non-PBC patients (P < 0.001) but not in PBC patients. No significant correlation was found in either group between gastrointestinal permeability and the other parameters. Conclusions Gastrointestinal permeability is increased in PBC. Portal hypertension contributes to altered gastric mucosal permeability in non-PBC cirrhosis, whereas different epithelial dysfunction can be hypothesized in PBC. (C) 2003 Lippincott Williams Wilkins.