To obtain the subject composition which has excellent hydroxyapatite crystal formation suppressive activity and is high in dental calculus preventive effect and excellent in using feel and safety by formulating a polycarboxylic acid derived from polysaccharides containing glucose anhydride as the constitution unit.

This composition contains a polycarboxylic acid, which is obtained by oxidizing polysaccharides (e.g. starch and the like) containing glucose anhydride as the constitution unit with an oxidizing agent (e.g. bleaching powder and the like) in the presence of a transition metal catalyst (e.g. ruthenium catalyst and the like) and possesses a weight-average molecular weight of preferably 1,000-100,000, in an amount of 0.01-10 wt.% based on the whole composition. Further, by using a divalent metal ion (e.g. magnesium ion and the like) in addition to the above polycarboxylic acid in amounts of 0.0001-1 wt.% based on the whole composition and 0.001-2 times weight based on the polycarboxylic acid, the hydroxyapatite crystal formation suppressive activity can further be improved.