PROBLEM TO BE SOLVED: To provide a composition for an oral cavity which can selectively and effectively remove stain deposited at a gap between prisms of surface layer of dental enamel and effectively prevent adhesion and deposition of new stain so as to give a tooth beautiful gross intrinsic to the tooth.SOLUTION: A composition for an oral cavity contains: (A) phytic acid or a salt thereof； and (B) tripolyphosphoric acid or a salt thereof. Total content of mass% of the component (A) in terms of the phytic acid and mass% of the component (B) in terms of the acid, and mass ratio ((B)/(A)) of mass% of the component (B) in terms of the acid to mass% of the component (A) in terms of the phytic acid are the specific values. The composition for an oral cavity does not contain a specific polyvalent metal or a salt (C) thereof, or contains the component (C) in an amount of less than 0.1-fold mole relative to mass% of the component (A) in terms of the phytic acid, and exhibits a pH of 5.5 or more to 6.5 or less when the composition for an oral cavity is diluted with water at concentration of 30 mass% at 25°C.SELECTED DRAWING: None【課題】歯のエナメル質表層の小柱間隙に存在する沈着した汚れを選択的かつ効果的に除去するとともに、新たな汚れが付着及び沈着するのをも有効に防止して、歯に本来有する美しい艶をもたらすことのできる口腔用組成物に関する。【解決手段】次の成分（Ａ）フィチン酸又はその塩、及び成分（Ｂ）トリポリリン酸又はその塩を含有し、成分（Ａ）のフィチン酸換算量と成分（Ｂ）の酸換算量との合計含有量、及び成分（Ｂ）の酸換算量と成分（Ａ）のフィチン酸換算量との質量比（（Ｂ）／（Ａ））が特定の値であり、特定の多価金属又はその塩（Ｃ）を含有しないか、或いは成分（Ａ）のフィチン酸換算量に対して成分（Ｃ）を０．１倍モル未満含有し、かつ水で３０質量％に希釈したときの２５℃におけるｐＨが５．５以上６．５以下である口腔用組成物。【選択図】なし
