Objective: To observe the toxicity effect of Cinnabaris on rat fertility and embryo development. Method: Cinnabaris suspension was orally administrated to SD male rats for six weeks and to female rats for two weeks intragastrically before matting at the doses of 1 000

300

100 mg ·kg-1 respectively

until the day males successfully mated and females was pregnant at D6.Male rats were sacrificed after mating

and female rats on D15 of pregnancy. The numbers of corpus luteum

implantation spot

and survival fetus were calculated. Blood cells

biochemistry

urine

and histo-pathological examination and analysis of all rats were carried out to compare with the control group. Result: There were significant differences in mean numbers of survival fetuses and pre-implantation embryo loss in 1 000 mg ·kg-1 group

although no significant differences in pregnant rates were seen. Blood cell and biochemistry examination showed that HGB

HCT

ALT

TP and ALB were significantly decreased as the doses increased in male rats. Pathological lesions were found in testicle

epididymis and seminal vesicle. Conclusion: Cinnabaris has toxicity effect on male rat fertility and early embryo development. Long term administration of Cinnabaris may inhibit erythrocytopoiesis and impair liver function. The functional and pathological changes may attribute to the toxicity of free mercury dissolved in blood.