Abstract: Using the mouse whole embryo culture technique,the teratogenicity of CP(5,10,15,20 mg·kg^-1)was investigated via intraper itoneal administration to Kun-Ming mice on day 8 of gestation,and the mechanism of its teratog enicity was also studied.Embryos were explanted and cultured 4 hours later.On day 10.5,culture was terminated and embryos were examined for yolksac diameter,head length and crown-rump leng th and teratogenic effects of CP.Significanttail defect was found in CP(15 mg·kg^-1)g roup and CP-induced growth retardation was greatest in CP(20 mg·kg^-1)group.Further results from transmission electron microscopy demonstrated some typical changes of apoptosis and cell death. These findings suggested that CP-induced apoptosis and/or cell death might be involved in its teratogenesis.