[en] To determine, by measuring the intracranial-parenchymal ratio at MR imaging, whether alcohol induces brain damage in social drinkers. One hundred and five male adults aged 20 or over were selected for this study. They inclued 41 non-drinkers, 43 mild to moderate social drinkers, nine heavy social drinkers and 12 alcoholics. Using a workstation, the intracranial-parenchymal ratio was measured at four levels of T1-weighted MR images: the fourth, third and lateral ventricle, and the level of the centrum semiovale. The mean ratios of all four levels (I-IV) were also calculated parenchymal ratios were compared between the four groups, and correlation between the amount of alcohol ingestion and the parenchymal ratio also determined. The parenchymal ratio at levels I-IV was 80.31±3.73% in non-drinkers, 79.38±4.39% in mild to moderate social drinkers, 80.92±3.64% in heavy social drinkers and 73.48±4.42% in alcoholics, The difference between alcoholics and the other three groups was statistically significant, but between non-drinkers and social drinkers was insignificant (ANOVA). Multiple regression analysis with control of the age factor revealed a decreased parenchymal ratio in mild to moderate and heavy social drinkers compared with non-drinkers, but without statistical significance. There was significant negative correlation between parenchymal ratio and amount of alcohol ingestion (pearson correlation). There was significant brain atrophy in alcoholics, but no significant difference between non-drinkers and social drinkers. We thus conclude that social drinking dose non induce significant alcohol-related brain atrophy