The reasons for the high frequency of endotoxaemia in cirrhosis, whether poor liver function or abnormal portal circulation, are not known. Accurate measurement of endotoxin itself is difficult. Instead, in this study an enzyme-linked immunosorbent assay was used to measure levels of IgA, IgG and IgM antibodies to endotoxin in patients with chronic liver disease and underlying hepatic viral infection. The relationships between the results and clinical symptoms or the presence of a portal systemic shunt were investigated. The median level of IgA antibodies was not different in patients with chronic hepatitis and those with cirrhosis, and the same was found for IgM, but the median level of IgG antibodies was significantly higher in the patients with cirrhosis. When patients with cirrhosis were grouped by the presence or absence of ascites or hepatocellular carcinoma, no significant difference was observed in any of these antibody levels. However, in cirrhotic patients with varices, the level of IgG antibodies to endotoxin was significantly higher than in patients without varices. For evaluation of the portal systemic shunt, the per-rectal portal shunt index was calculated. There was a significant correlation (R = 0.431, P < 0.001) between the per-rectal portal shunt index and the level of IgG antibodies to endotoxin. That is, the degree of abnormality in the portal haemodynamics was correlated with the level of IgG antibodies to endotoxin in patients with liver disease.