To find a substance that can control, from outside the body, CXCL12 composing the niche of pigment stem cells and involved in the suppression of pigment stem cell differentiation, and to provide this as an agent for fundamentally and efficiently preventing and/or improving gray hair.SOLUTION: Provided is a CXCL12 (stromal cell-derived factor-1) expression promoter, and the suppressing agent of pigment stem cell differentiation, characterized by containing as active ingredients truffle extract and one or two extracts selected from the extract of Panax ginseng that has been heat-dried after steam heat treatment.SELECTED DRAWING: None【課題】色素幹細胞のニッチを構成し、色素幹細胞の分化抑制に関与するＣＸＣＬ１２を生体の外部から制御できる物質を見出し、これを、白髪を根本的にかつ効率的に予防及び／又は改善するための薬剤として提供すること。【解決手段】トリュフの抽出物、及び蒸気加熱処理後、加熱乾燥処理されたオタネニンジンの抽出物から選ばれる１種又は２種の抽出物を有効成分として含有することを特徴とする、ＣＸＣＬ１２（ｓｔｒｏｍａｌ ｃｅｌｌ-ｄｅｒｉｖｅｄ ｆａｃｔｏｒ－１）の発現促進剤、及び色素幹細胞の分化抑制剤。【選択図】なし
