Abstract:Abstract: Objective To inquire into the effect of N-butyl alcohol and ethyl acetate extracts of Geranium Strictipes extracted by different methods on growth and acid production of Streptococcus mutans, Streptococcus sanguis and Actinomyces viscosus. Methods Firstly, minimum bacteriostatic concentration (MIC) and minimum bactericidal concentration (MBC) of N-butyl alcohol and ethyl acetate extracts of Geranium Strictipes extracted by different methods on Streptococcus mutans, Streptococcus sanguis and Actinomyces viscosus were respectively determined and then the effect of these Geranium Strictipes extracts on the acid production was determined. Results The MIC of N-butyl alcohol extract of Geranium Strictipes extracted reflux on Streptococcus mutans, Streptococcus sanguis and Actinomyces viscosus were 3.0, 3.0 and 6.0 g/L respectively, while the MBC were 6.0, 6.0 and 12.0 g/L respectively. The MIC of ethyl acetate extract of Geranium Strictipes extracted reflux on the three bacteria strains were all 6.0 g/L, and the MBC were all 12.0 g/L. The MIC of N-butyl alcohol extract of Geranium Strictipes extracted maceration on the three bacteria strains were all 6.0 g/L, the MBC were all 12.0 g/L. The MIC of ethyl acetate extract of Geranium Strictipes extracted maceration on the three bacteria strains were all 6.0 g/L, the MBC were all 12.0 g/L. A certain concentration of N-butyl alcohol and ethyl acetate extracts of Geranium Strictipes could inhibit acid production of the three bacteria strains, but there was no significant difference in the inhibition of acid production by different extraction methods. Conclusions N-butyl alcohol and ethyl acetate extracts of Geranium Strictipes can effectively inhibit the growth and acid production of oral bacteria, may be effective anti-caries agents.