Abstract: By the methods of acute toxicity test and single cell gel electrophoresis (comet assay),this paper evaluated the toxicological effects of three veterinary drugs olaquindox,arsanilic acid and oxytetracycline on earthworm (Eisenia foetida) coelomocytes in vivo.The results of acute toxicity test showed that only the highest dose of olaquidox caused the death of some earthworms,and none of the test drugs had any effects on earthworm at their environmentally relevant concentrations.The comet assay indicated that arsanilic acid had no genotoxicity to earthworm,while olaquindox and oxytetracycline induced significant DNA damage in earthworm coelomocytes (P<0.01).

Key words: Bt transgenic cotton, Ecological risk, Risk assessment, Insect resistance, IPM