The influence of dietary disulfiram (97778) upon the tissue distribution and excretion of orally administered 1,2-dibromoethane (106934) was investigated. Male Sprague-Dawley-rats were given 0.05 percent disulfiram in their food for 12 days. Animals were then given single 4 gram per kilogram doses of carbon-14 labeled 1,2- dibromoethane. At 24 and 48 hours after treatment, the rats were sacrificed and tissue distribution of 1,2-dibromoethane was determined. Tissue radioactivity levels were significantly greater in the liver, kidneys, spleen, testes, and brain of the rats receiving disulfiram than in comparisons receiving no pretreatment. The rate of clearance of radioactivity was appreciably lower in the disulfiram group, especially for clearance from the testes. Radioactivity levels in liver nuclei obtained from the disulfiram treated animals were significantly greater than in the comparisons. The authors suggest that nuclear uptake of 1,2-dibromoethane in disulfiram treated animals is related to the development of liver tumors.