To explore the
developmental toxicity caused by Eucommia Bark,
Baikal Skullcap root and Ramie root which were always being
applied to prevent abortion,the adults and regenerators of Hydra were exposed to test chemicals respectively.Accordintg to their morphological changes and wilby's score method,median toxic concentration(T_(50)) in adults and median inhibition concentration(I_(50)) in regenerators were calculated,then T_(50)/I_(50) ratios was gotten as a index of teratogenesis.In the assay of teratogenesis,T_(50)/I_(50) ratios of Eucommia Bark、
Baikal Skullcap root and Ramie root were 0.9、3.2、1.9 respectively,showing the concentration_response relationship.In the following assay,the teratogenesis induced by colchicine could be restrained by Eucommia Bark with concentration_response relationship.According to wilby's teratogenic criteria,Eucommia Bark possessed a negative teratogen and accelerated the differentiation and antagonized teratogenesis of colchicine in the Hydra regenertors;Baikal Skullcap root showed distinctly positive as a teratogen;Ramie root belonged to a positive teratogen in this short_term assay in vitro.