The present study explored the utility of erythrocyte aldehyde dehydrogenase (ALDH) as a peripheral marker in alcoholism. The ALDH levels in aocoholics, their first degree nonalcholic relative and controls were compared. ALDH was found to be significantly lower in alcoholics (3.38±1.70 mU p< 0.001) and their first degree relatives (4.04±1.55 mU p< 0.05) compared to controls (5.06±1 55mU). Low ALDH levels among alcoholics persisted despite abstinence. The levels did not correlate with indices of hepatic dysfunction or with severity of alcoholism. These findings indicate that low erythrocyte ALDH may be considered as a biochemical trait marker associated with alcoholics, and the alcohol abuse would further decrease enzyme activitiy. To evaluate this proposition, logitudinal studies involving high risk progeny of alcohol dependents is being planned.