The possible role of HBV infection in the progression of alcoholic liver disease remains debated. However, serum HBV markers in alcoholics, although present with a high frequency, mainly consist of anti-HBs and/or anti-HBc antibodies. In order to detect an HBV multiplication that could be missed by the usual markers, we looked for HBV-DNA in the serum of 146 chronic alcoholics; the results were compared with those of the usual serological HBV markers. Sixty-eight of the 146 patients could be studied for HBV-DNA both in the liver and the serum. The 146 alcoholics were divided in 48 with normal liver function (group I); 67 with non-cirrhotic alcoholic liver disease (group II); 31 with alcoholic cirrhosis (group III). Among the 146 patients, 17 had a viral multiplication reflected by serum positive HBV-DNA, as against none of 100 healthy controls (P less than 0.01). Six of the 17 had a normal liver function (6/48 = 12.5%), 7 were of group II (7/67 = 10.4%) and 4 had cirrhosis (4/31 = 12.9%). Serum HBV-DNA was associated with HBsAg in 3 occasions; in addition serum HBV-DNA was also present in 5 HBsAg-negative patients with anti-HBc and/or anti-HBs and even in 9 without any usual HBV marker. The overall prevalence of HBV markers in the 146 patients went from 30.8% to 37.0% when serum HBV-DNA was taken into account; it was similar in the 3 groups studied. Eight patients, of the 68 studied, were liver HBV-DNA-positive.(ABSTRACT TRUNCATED AT 250 WORDS)