The present invention relates to a composition for oral cavity having improved solubility while maintaining good coaggregation inhibitory effect of alkylgalactoside. The present invention relates to the following component (A) represented by the following formula (I): (wherein R represents an optionally substituted linear or branched alkyl group having 8 to 18 carbon atoms； Represents a galactose residue, E represents a hydrogen atom or a methyl group, m represents an integer of 0 to 200, and n represents an integer of 1 to 30.) 0.001% by mass or more and 1 The composition for oral cavity containing the mass% or less, (B) Cationic disinfectant 0.001 mass% or more and 0.1 mass% or less, and (C) 35 mass% or more of water.【課題】アルキルガラクトシドの共凝集抑制効果を良好に保持しながら、その溶解性を高めた口腔用組成物に関する。【解決手段】本発明は、次の成分（Ａ）下記式（Ｉ）： （式中、Ｒは置換されてもよい炭素数８～１８の直鎖又は分岐鎖状のアルキル基を示し、Ｇはガラクトース残基を示し、Ｅは水素原子又はメチル基を示し、ｍは０～２００の整数を示し、ｎは１～３０の整数を示す。）で表される化合物 ０．００１質量％以上１質量％以下、（Ｂ）カチオン性殺菌剤 ０．００１質量％以上０．１質量％以下、及び（Ｃ）水 ３５質量％以上を含有する口腔用組成物。
