Objective:The purpose of this study is to demonstrate the decomposition and removal effects of dextranase-containing toothpaste on dental plaque. Method:In the decom-position test,the supatant of three times diluted toothpaste was applied to a dextran solu-tion (as a dental model plaque),and samples were evaluated by colorimetric reaction with Fehling’s test solution. In the removal test,the supatant of three times diluted toothpaste was applied to a dental model plaque prepared with Streptococcus mutans and the optical den-sity at 550nm (hereinafter referred to as OD550 )was measured as the remaining plaque. Re-sults:In the test solution of toothpaste containing dextranase,a red-brown precipitate was observed. On the other hand,a precipitate was not observed in the test solution of the placebo toothpaste which did not contain dextranase. The plaque removal effect of the test toothpaste was 2. 7 times higher than that of the placebo toothpaste. Conclusion:Our findings suggest that the test toothpaste containing dextranase has a higher plaque removal effect by cutting α-1,6-linkages inside the plaque. Therefore,the test toothpaste might be helpful to prevent dental caries.