Targeted at, for example, mammalian animals including human, and for the purpose of realizing an effective reduction in the malodor inherent to flatulence and/or stool with an orally ingestible material such as an inorganic substance, provided is an orally ingestible malodor reducing agent for reducing the malodor of flatulence and/or stool, the agent containing nanosized colloidal platinum microparticles as an active ingredient.

Targeted at, for example, mammalian animals including human, and for the purpose of realizing an effective reduction in the malodor inherent to flatulence and/or stool with an orally ingestible material such as an inorganic substance, provided is an orally ingestible malodor reducing agent for reducing the malodor of flatulence and/or stool, the agent containing nanosized colloidal platinum microparticles as an active ingredient.