Authors showed the inhibitory effect of Cepharanthin, a kind of Alkaloid, on the teratogenicity of maternal hypervitaminosis A in the rat in the previous report. At the present study, besides, the effect to the internal malformations induced by maternal hypervitaminosis A were investigated using the same materials of the previous study. Twenty-four fetuses from 2 mothers treated with excessive vitamin A and 31 from 3 mothers treated with both of excessive vitamin A and Cepharanthin were stained with Inouye's bone and cartilage staining method and the findings of their middle ear region were observed under the light stereoscopic microscope. Difference of middle ear findings between 2 groups suggested that the inhibitory effect of Cepharanthin to the teratogenic activity of excessive vitamin A acts even on the internal malformations of middle ear region by the membrane stabilizing effect of Cepharanthin.
