These studies are concerned with detection of circulating antibodies against various defined enterobacterial antigens in patients with chronic inflammatory liver diseases such as chronic hepatitis type B (n =46). chronic active hepatitis (CAH) of autoimmune type (n =10). alcoholic cirrhosis (n = 24) and primary biliary cirrhosis (PBC) (ti =24) as well as in healthy individuals (n= 39). Anti-LPS and anti-lipid A were determined by hemolytic and hemagglutination assay. Immunoblot technique was used to investigate the antibody activity against plasmid encoded proteins from Yersinia enterocolitica. Persistent titers of anti-LPS up to serum dilution 1:32.768 were found with hemolytic and hemagglutination assay in patients with alcoholic cirrhosis or PBC and in healthy control. In contrast nearly 50% of patients with chronic hepatitis B had no hemolytic antibodies against the two LPSE. coliserotypes at the time of liver biopsy. Anti-lipid A was detectable in 58% of patients with alcoholic cirrhosis but in low titers in less than 10% in the other groups (p<0.001). Alcoholic cirrhosis was also associated with a high frequency of IgG and IgA antibodies against plasmid encoded proteins from Yersina enterocolitica. The data indicate that the 0–polysaccharides as strong antigens are physiologically exposed to the immune system while lipid A and enterobacterial proteins are solely immunogenic under abnormal conditions.