This invention relates to a use of hederagenin 3-O-α-L-rhamnopyranosyl((1→2)-[β-D-glucopyranosyl(1→4)]-α-L-arabinopyranoside or a Pulsatillae radix extract containing the same as a therapeutic agent for solid tumors. Also, this invention relates to a method of preparing a therapeutic agent for solid tumors by using hederagenin 3-0-α-L-rhamnopyranosyl(1→2)-[β-D-glucopyranosyl(1→4)]-α-L-arabinopyranoside, or a method of treating a subject suffering from solid tumors, comprising administering to the subject a therapeutically effective dose of hederagenin 3-0-α-L-rhamnopyranosyl(1→2)-[β-D-glucopyranosyl(1→4)]-α-L-arabinopyranoside.