Ecdysterone was isolated from the root of Formosan Achyranthes obtusifolia LAM. (Japanese name "Shimainokozuchi"), with two crystalline components of m.p. 248°(decomp.) and of m.p. 230°(decomp.). This contrasts with the fact that ecdysterone and inokosterone were isolatd in approximately an equal amount from the root of Japanese A. fauriei LEV. ET VAN. (Japanese name "Hinata-inokozuchi").