OBJECTIVETo investigate the characteristics of embryonic toxicity of Senecio scandens, its total alkaloid and Qianbai Biyanpian so that to provide guidance for the safety of medication during pregnancy.METHODTwo hundred and twenty pregnant SD rats were divided into 11 groups: control group, positive group (cyclophosphamide 10 mg x kg(-1)). Water extract of S. scandens (doses: 7.5, 15.0, 30.0 g herb of S. scandens per kilogram body weight respectively). Qianbai Biyanpian and total alkaloid at the same doses levels with the water extract of S. scandens (doses were expressed as herb of S. scandens per kilogram body weight). The test articles were given to the pregnant rats by gavage from day 6 to day 15 of pregnancy. Body weight and the food consumption of pregnancy rats, and fetal weight and length were measured. The number of absorbed and dead embryos was recorded. Fetuses were examined in viscus and bones.RESULTWeight and the food consumption of pregnancy rats in high-dose of Qianbai Biyanpian and total alkaloids decreased. All treatment groups had no significant change in the number of absorbed embryos, but the stillbirths were significantly increased in high-dose groups of water extract and total alkaloids as compared with control group. Bone deformities such as fontanel expanding, hypoplasia of parietal bone, occipital bone and cervical arch were observed. Rib abnormality could also be seen in some rats. All water extract of S. scandens, Qianbai Biyanpian and total alkaloid could cause the bone abnormalities, but the percentage of bone deformities of total alkaloids was the highest (up to 80%).CONCLUSIONS. scandens and its total alkaloids, its formula Qianbai Biyanpian can cause rat skeletal deformities in fetuses when they were given during pregnancy. It is suggested that S. scandens and the product containing S. scandens should not be used during pregnancy.