Objective　To evaluate the effects of propolis on the growth of S.mutans ATCC 25175 (S.m)

S.sobrinus 6715 (S.s) and their fluorideresistant strains (S.m-FR

S.s-FR)

and the change of their glucosyltransferase (GTF). 　Methods　S.m and S.s were induced with sodium fluoride by minimum inhibitory concentration (MIC) to induce fluorideresistant strains (S.m-FR and S.s-FR). Fluid dilution method was used to observe the effects of different levels of propolis on growth of S.m

S.m-FR

S.s and S.s-FR. Chemistry enzyme analysis was used to detect the influence of propolis on the enzyme activity of GTF. 　Results　MIC of propolis for S.m

S.m-FR

S.s and S.s-FR were respectively 0.39

0.78

0.20 and 0.39 g/L. MBC of propolis for them were respectively 0.78

1.56

1.56

and 1.56 g/L. GTF of S.m

S.m-FR

S.s

and S.s-FR was decreased gradually with the increase of concentration of propolis. There were significant differences among total sample groups

and each experimental group and positive control group as well (P0.05). 　Conclusion　Propolis effectively inhibits the growth of S.m

S.m-FR

S.s and S.s-FR

and inhibits the GTF activity.