PROBLEM TO BE SOLVED: To provide an odor composition comprising an alarm pheromone which can be used as a repellent for mammals, particularly rodents.SOLUTION: An odor composition comprises (A) methylpentanal and (B) hexanal.SELECTED DRAWING: NoneCOPYRIGHT: (C)2016,JPO&INPIT【課題】哺乳類、特にげっ歯類等の忌避剤として使用し得る警報フェロモンを含有する臭気性組成物の提供。【解決手段】(A)メチルペンタナール及び(B)ヘキサナールを含有する臭気性組成物。【選択図】なし