A composition for use in the oral cavity is disclosed. The composition comprises (A) an antibacterial compound represented by the following general formula (1),A.sup.m+ .multidot.X.sub.m.sup.- (1)wherein A.sup.m+ is a nitrogen-containing antibacterial cation and the counter anion X.sup.- represents a monoalkyl phosphate ion, a monoalkenyl phosphate ion, a monoalkyl phosphonate ion, or a monoalkenyl phosphonate ion having a linear or branched alkyl or alkenyl group with 8 to 20 carbon atoms, and m is a valence of the cation A, and (B) a vehicle for use in the oral cavity. It exhibits a remarkablely rapid and continued disinfection effect action against oral cavity bacteria, while providing a good taste. Its disinfection effect is not reduced in the presence of surfactants. In addition, it does not color the tooth.