Increased in vivo synthesis of immunoglobulin in patients with alcoholic liver damage has been attributed to direct activation of B cells, although other defects of lymphocyte function have been identified suggesting a more generalised defect. In the present study we have investigated the role of T cell regulation of immunoglobulin production in alcoholic liver disease analysed according to the presence or absence of alcoholic hepatitis. Spontaneous production of IgG and IgA was elevated and co-culture experiments confirmed hyper-reactivity of B cells, but also suggested impaired T cell function. Suppressor cell activity for IgG and IgA was impaired. Similarly, the response to pokeweed mitogen for IgG and IgA was defective, although this was more marked for secretion than for proliferation suggesting an associated T helper defect. No differences in the immunological abnormalities were identified between those with alcoholic hepatitis and those with other alcoholic liver diseases. This study demonstrates a broad defect of T cells and a hyper-reactivity of B cells in patients with alcoholic liver disease, irrespective of the severity of hepatic inflammation.