PROBLEM TO BE SOLVED: To provide a technique that allows a stem cell to proliferate while maintaining its undifferentiated state.SOLUTION: The present invention provides an agent for maintaining the undifferentiated state of a stem cell or promoting its proliferation, the agent comprising lemon extract as an active ingredient.COPYRIGHT: (C)2016,JPO&INPIT【課題】幹細胞を、未分化状態を維持させたまま増殖させることができる技術を提供することを目的とする。【解決手段】レモンの抽出物を有効成分として含有する幹細胞の未分化状態維持剤又は増殖促進剤。【選択図】なし