Abstract: OBJECTIVE： To assess whether there was a teratogenic risk from Cyperus esculentus on SPF grade pregnant SD rats. METHODS： For this study，100 3-month-old SPF grade and pregnant rats were used. They were weighed on the 0^th，6^th，9^th，12^th，15^th，and 20^th days of gestation. On the 6^th to 15^th days of gestation，rats were fed at four concentration levels of Cyperus esculentus：0 (CK)，2，4，and 8 g/kg body weight. The pregnant rats were sacrificed using CO₂ anesthesia on the 20th day of gestation. The uterus was taken out by laparotomy，and the weights of the uteri and fetuses were measured. The numbers of corpora lutea，implantation，absorption，early death，late death，and live fetus were recorded and examined. The fetal weights and body lengths were recorded for live fetal rats，and they were examined for abnormalities. RESULTS： For the pregnant rats，no abnormal physical signs were found，their general activities were normal，and no significant abnormalities were found in gross anatomy at the 20^th day of execution. Results from analysis of the data show that Cyperus esculentus had no effect on the general situation，body weight and weight gain，embryonic development，fetal mouse appearance abnormalities，fetal mouse bone development，skeletal teratogenesis rate，fetal mouse visceral development，teratogenesis rate，and total teratogenesis rate of pregnant rats. CONCLUSION： Under our experimental conditions，there was no difference in abnormalities among the different exposure dose groups and from the controls. Thus，it can be determined that Cyperus esculentus did not cause teratogenic risk under our experimental conditions.

Key words: Cyperus esculentus, teratogenicity, SD pregnant rat, teratogenesis rate