A history of gastrectomy was more frequently encountered in Japanese male alcoholics (9.7%, 47/486) than in male employee populations of two large companies (0.8%, 36/4,381, p < 0.001, and 0.6%, 6/950, p < 0.001). Gastrectomized men are known to achieve a higher blood ethanol level after the ingestion of the equal amount of ethanol than nongastrectomized men. To examine whether or not gastrectomy was responsible for the subsequent development of alcohol dependence, 47 gastrectomized alcoholics were compared with 47 age-matched nongastrectomized alcoholics. The mean lifetime duration of heavy drinking (> 120 g ethanol/day) was shorter in the former than in the latter (11 +/- 10 years vs. 16 +/- 9, p < 0.05), and the mean lifetime cumulative ethanol consumption level also smaller (834 +/- 497 kg vs. 1047 +/- 508, p < 0.05). The majority of gastrectomized patients (30/47) had no history of problem drinking before gastrectomy. The daily consumption was rapidly increased within 5 years after gastrectomy in 18 of 38 habitual drinkers (47%). Seven of the remaining nine nonhabitual drinkers (78%) became habitual drinkers and alcoholics within a short period of time (7 +/- 4 years), though with low lifetime cumulative consumption (< 400 kg). The incidence of disorders of the central and peripheral nervous systems observed did not differ between the two groups, except for frequent alcoholic blackouts reported in the gastrectomized patients. In conclusion, the majority of the gastrectomized patients changed their drinking habits after gastrectomy and developed alcohol dependence. They did not require as much lifetime cumulative ethanol as nongastrectomized patients to become ethanol dependent.