OBJECTIVES: Alcohol-induced oxidative stress has been known to injure various tissues or organs. This stress is related with free radicals which are produced as the result of long-term alcohol consumption. Malonyldialdehyde(MDA) is produced by the interaction of free radicals and cell membrane lipids, and indicates the degree of lipid peroxidation indirectly. The purpose of this study was to investigate the relationship between red blood cell(RBC) membrane lipid peroxidation by free radicals, and associated hepatic injuries and hematologic changes. METHODS: Thirty-three subjects diagnosed as alcohol dependence according to DSM-IV diagnostic criteria were evaluated within 72 hours after discontinuing alcohol drinking. Clinical characteristics were evaluated by CAGE questionnaire and Korean Michigan Alcoholism Screening Test(MAST). RBC membrane MDA level was measured as the marker of RBC membrane lipid peroxidation. Aspartate aminotransferase(AST), alanine aminotransferase(ALT) and gamma-glutamyltransferase(GGT) were used as the biochemical markers of liver damage due to alcohol ingestion. The alcohol-induced hematologic change was assessed by mean corpuscular volume(MCV). RESULTS: The results were as follows. Clinical characteristics were not different between two groups having normal and abnormal levels of AST, ALT, GGT or MCV. The levels of MDA were not correlated with the clinical characteristics and serum levels of AST, ALT and GGT. However, there was a significant correlation between the levels of MDA and the value of MCV(p=0.017). CONCLUSIONS: These findings suggest that oxidative stress in alcohol dependence may not be reflected in liver enzyme markers such as AST, ALT and GGT, but may be reflected in MCV.