Provided is an oral composition for denture wearers, which includes an antimicrobial substance of biological origin, is biocompatible, and has an antimicrobial activity. Specifically, provided is an antimicrobial oral composition for denture wearers including a component of common rush origin. The oral composition for denture wearers is placed in the mouth, and hence the oral composition for denture wearers including a component of common rush origin, which may also be used as a food additive, is safe for a living body and useful.