After screening 408 crude drugs, we found that Rizoma Arisaematis increased the cell numbers of mouse blastocysts developed from in vivo zygotes. We examined the effects of Rizoma Arisaematis on the in vitro development of mouse zygotes and embryos produced by ICSI and SCNT, as well as on fetal development. Mouse zygotes were cultured in media containing a water-soluble extract of Rizoma Arisaematis at various concentrations, and the potential of zygotes to develop into blastocysts and the cell numbers of blastocysts were examined. In addition, the effects of Rizoma Arisaematis on the in vitro and in vivo developmental potential of embryos produced by ICSI and nuclear transfer were examined. In vitro treatment of zygotes with Rizoma Arisaematis increased the cell numbers of blastocysts. The proportions of the blastocysts that implanted and developed into fetuses were slightly higher in the blastocysts which were developed from zygotes treated with Rizoma Arisaematis than those of the control. The Rizoma Arisaematis treatment of mouse fetal fibroblast cells or embryos produced by ICSI and SCNT did not affect the growth of the cells, or the in vitro development of the zygotes. The present study demonstrated that Rizoma Arisaematis improved the quality of embryos developed from in-vivo zygotes, but not that of embryos produced by ICSI and nuclear transfer.