Abstract: Purpose : To study sarin toxicity effect on human chromosomes. Methods : Frequency of sister2chromatid exchanges (SCEs) was measured in lymphocytes of 8 victims of Tokyo sarin t ragedy and 49 cont rols and statistical analysis was employed. Results : The mean f requency of exposure group was (4. 916 ±1. 480) / cell.The slightly significant difference was found as compared with the mean f requency (3. 766 ±0. 620) / cell of cont rol (Cochran t test , one tail , P < 0. 05) . Conclusion : The positive result may probably be due to an excess of at ropine (a possible teratogenicity) during emergency t reatment of by three victims with severe symptoms. Proportion was 1∶95 , 1∶25 between dose accumulated of at ropine and dose estimated of sarin. A finally conclusion requires logical and authentic experiment s and more long-term epidemiological investigation. In the t reatment of organophosphorus pesticide poisoning , a compound and altrnate application of special alexipharmic and cholinesterase reactivating agent must be emphasized in order to reduce the possible side effect s of drugs as much as possible.

Key words: sarin, atropin, lymphocyte, SCE, dose exposed