Abstract: Objective: The effects of extraction site of ethyl acetate of Piper betle's fruit on the growth and metabolism of two kinds of
cariogenic bacteria（Streptococcus mutans and Actinomyces viscosus）were studied. Methods: The minimum inhibitory concentration
（MIC）and minimum bactericidal concentration（MBC）of two kinds of cariogenic bacteria in the extraction site of ethyl acetate were determined by double dilution method with Chlorhexidine as the positive control group. The effects of 4 concentrations of ethyl acetate extraction lower than MIC on the metabolism of two kinds of cariogenic bacteria were determined. Results: The MIC values of the extraction site of ethyl acetate against Streptococcus mutans and Actinomyces viscosus were 6.250 mg/mL and 3.125 mg/mL respectively,and the MBC values were 12.500 mg/mL and 6.250 mg/mL respectively. All the 4 concentrations at the extraction site of ethyl acetate inhibited the acid production of Actinomyces viscosus, and the high concentration group inhibited the acid production of Streptococcus mutans. Conclusion: The inhibition effect of ethyl acetate extraction on Actinomyces viscosus was stronger than that on Streptococcus mutans. The inhibition effect of acid production was positively correlated with the concentrations, but the effects were all weaker than those in the positive control group.

Key words: fruit of Piper betle, ethyl acetate extraction site, cariogenic bacteria, bacteriostat, acid production