PROBLEM TO BE SOLVED: To provide a TRPV4 activity inhibitor that inhibits TRPV4 activity and is useful for IBS prevention or improvement, and an agent for preventing or improving IBS.SOLUTION: A TRPV4 activity inhibitor contains at least one selected from rosmarinic acid, dimethyl rosmarinic acid and a salt or solvate thereof as an active ingredient.SELECTED DRAWING: NoneCOPYRIGHT: (C)2019,JPO&INPIT【課題】TRPV4の活性を抑制し、IBSの予防又は改善に有用なTRPV4活性抑制剤、IBSの予防又は改善を提供する。【解決手段】ロズマリン酸 、ジメチルロズマリン酸及びそれらの塩若しくは溶媒和物から選択される1種以上を有効成分とするTRPV4活性抑制剤。【選択図】なし