PROBLEM TO BE SOLVED: To provide a composition for oral cavity in which the stability of ascorbic acid phosphate ester or salt thereof is improved and reduction in residual ratio of ascorbic acid phosphate ester or salt thereof and discoloration of preparation after preservation are suppressed; and a method for improving the stability of ascorbic acid phosphate ester or salt thereof in a composition for oral cavity.SOLUTION: The invention provides a composition for oral cavity, the composition comprising 0.02-1 mass% of (A) ascorbic acid phosphate ester and/or salt thereof and 0.01-1.8 mass% of (B) lactoferrin. The invention also provides a method for improving stability of ascorbic acid phosphate ester and/or salt thereof in a composition for oral cavity, in which 0.01-1.8 mass% of (B) component is compounded in the composition for oral cavity that contains 0.02-1 mass% of (A) component.
