The purpose of the present invention is to provide a sole component that can exhibit a function as an oral composition, such as the prevention of dentinal caries, the prevention or amelioration of dentin hypersensitivity, the inhibition of the formation of stains, the removal of stains or the like, or a combination of two or more of such components. The present invention provides an oral composition containing a component (A) which is a compound having at least one lactam skeleton selected from the group consisting of a gamma-lactam skeleton, a delta-lactam skeleton and an epsilon-lactam skeleton and also having an acidic group and/or a salt of the compound.
