【Abstract】ObjectiveTo study the specific cytotoxicity of amygdalin(a new prodrug) to LoVo cells in antibody directed enzyme prodrug therapy (ADEPT). MethodsThe specific activation of amygdalin by anti-CEA McAb-β-glucosidase conjugate and the cytotoxicity of amygdalin to LoVo cells were assessed throughTrypan blue exclusion. ResultsThe cytotoxicity of amygdalin itself to LoVo cells was low. However, when amygdalin was combinated with anti-CEA McAb-β-glucosidase conjugate, its cytotoxic effect was enhanced by nearly 40 times, and that effect was specific to to LoVo cells expressing CEA . When LoVo cells and MCF-7 cells were co-cultured in various ratios, the cytotoxic effect of amygdalin combinated with anti-CEA McAb-β-glucosidase conjugate was measured. The survival rate of cultured cells decreased while the percentage of LoVo cells increased, suggesting the cytotoxic effect to be specific to LoVo cells. ConclusionThe toxicity of amygdalin is low，and it can be activated by anti-CEA McAb-β-glucosidase conjugate effectively to kill targetd cells specifically which may be a new way for colorectal tumor therapy.