Alcohol abuse can induce brain atrophy, but it only occurs in some alcoholics. To investigate whether genetic polymorphism of alcohol-metabolizing enzymes [including alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH)] was related to alcoholic brain atrophy, we determined restriction fragment-length polymorphisms of the ADH2 and ALDH2 genes in 77 male alcoholics. Computed tomography was used to determine the severity of brain atrophy. Digestion with MaeIII and MboII after polymerase chain reaction amplification showed that the ADH2(1) gene frequency was significantly higher in patients with brain atrophy than in those without brain atrophy (chi 2 = 9.274, p < 0.01), whereas no significant association was observed between brain atrophy and the ALDH2 gene Multivariate analysis (including age, total alcohol intake, liver cirrhosis, and ADH2 genotype) showed that the ADH2(1)/ADH2(1) genotype was associated with alcoholic brain atrophy. These findings suggest that the ADH2(1) allele may be associated with alcoholic brain atrophy.