OBJECTIVE: Nitric oxide(NO) has been known to be associated with tolerance and preference to alcohol. It has also been known to affect various alcohol drinking behavior, alcohol withdrawal symptoms and alcohol-induced brain damage. The purpose of this study was to determine the difference, among alcohol dependence group, alcohol drinking group and abstinence group, in serum concentration of nitrite, a stable metabolite of NO, and it's relationship to clinical and biochemical markers of alcoholism. METHODS: Forty subjects diagnosed as alcohol dependence according to DSM-IV diagnostic criteria were evaluated for the clinical characteristics and biochemical markers of alcohol dependence including nitrite with their CIWA-Ar scores checked just after admission. Thirty-nine healthy controls were also evaluated, divided into twenty-three alcohol drinking group and sixteen abstinence group. Clinical characteristics were evaluated by CIWA-Ar, CAGE and AUDIT questionnaires. Aspartate aminotransferase(AST), alanine aminotransferase (ALT), gamma glutamyltransferase(GGT) and mean corpuscular volume(MCV) were used as the biochemical markers of alcohol dependence. Serum nitrite concentrations were measured by Griess reaction. RESULTS: 1) The concentrations of nitrite in alcohol dependence patients were not different from those in the control subjects. 2) There were no significant association between the nitrite concentrations and the CIWA-Ar scores in alcohol dependence patients. 3) Nitrites are significantly increased in alcohol dependence group and alcohol drinking group compared with abstinence group. CONCLUSIONS: These findings suggest that serum nitrite concentration has no relation with alcohol withdrawal symptoms, but alcohol drinking increases serum nitrite concentration influenced by general condition of the body.