Including the fucoidan-containing material or fucoidan, side effects inhibitors of drug therapy for colorectal cancer using 5-fluorouracil, and characterized in that it is administered to patients with colorectal cancer fucoidan-containing material or fucoidan, the present invention uses a 5-fluorouracil to provide a method of inhibiting side effects drug therapy of colon cancer, for the manufacture of side effects inhibitors of drug therapy of colon cancer as well as using 5-fluorouracil, the use of fucoidan-containing material or fucoidan.本発明は、フコイダンまたはフコイダン含有素材を含む、5-フルオロウラシルを用いる大腸癌の薬物療法の副作用抑制剤、フコイダンまたはフコイダン含有素材を大腸癌患者に投与することを特徴とする、5-フルオロウラシルを用いる大腸癌の薬物療法の副作用抑制方法、ならびに5-フルオロウラシルを用いる大腸癌の薬物療法の副作用抑制剤の製造のための、フコイダンまたはフコイダン含有素材の使用を提供する。
