Abstract: Objective: To investigate the antibacterial activities to periodontal pathogens (Porphyromonas gingivalis, Pg; Actinomycetemcomitans actinobacillus, Aa; Fusobacterium nucleatum, Fn) by propolis in different menstruums of different concentrations. Method: To use filter paper and multiple dilute propolis solutions, so as to compare the effects of the solution of different concentrations, and find the minimum inhibitory concentrations(MIC). Results: The propolis in different menstruums has different effects, in the order: 95% ethanol > 70% ethanol > glycerin solution > water. The effect reduce when the concentration falls. The effects differ on three test pathogens, Pg > Fn > Aa. Propolis solution of 95% ethanol and 70% ethanol shows evidence antibacterial activities on Pg and Fn, and the effects reduce when the concentration falls. High concentration propolis solution of glycerin also shows antibacterial activities on test pathogens. In this research propolis solution of water has no distinct activities.

Key words: propolis, antibacterial activities, periodontal pathogens