PROBLEM TO BE SOLVED: To provide a TRPV4 (Transient receptor potential cation channel subfamily V member 4) activity inhibitor, as well as an agent for prevention or improvement of irritable bowel syndrome that utilizes effects of the TRPV4 activity inhibitor and serves as means for administration thereof.SOLUTION: The invention provides a TRPV4 activity inhibitor comprising Perilla frutescens extract or perillaldehyde as an active ingredient. The invention also provides an agent for preventing or improving irritable bowel syndrome.SELECTED DRAWING: None【課題】TRPV4(Transient receptor potential cation channel subfamily V member 4)活性阻害剤、及びTRPV4活性阻害剤の効能を生かし、またその投与の手段としての、過敏性腸症候群の予防又は改善剤を提供する。【解決手段】シソ(Perillafrutescens)抽出物又はペリルアルデヒドを有効成分とする、TRPV4活性阻害剤、並びに過敏性腸症候群の予防若しくは改善剤。【選択図】なし
