Objective    To evaluate the effects of propolis on the growth of porphyromonas gingival (Pg) and its toxical influence on human gingival fibroblast (HGF).     Methods    Minimal bactericidal concentration (MBC) of propolis on Pg was determined by the fluid dilution method. The relative growth rates (RGR) and the proliferation status were determined by MTT assay after HGF was incubated in culture solution containing propolis for 24 h.     Results    MBC of propolis to Pg was 1.56 g/L

which was equal to 0.125 to 0.25 mg/L ornidazole. The RGR of HGF was more than 70% when propolis was 1.56 g/L. The number of HGF kept increasing for 7 d and approached negative control group after being treated by 4 g/L propolis

and RGR of  HGF was 52.1 % after 24 h.     Conclusion    Propolis can significantly inhibit the growth of Pg

and its cytotoxical effect was weak and reversible.  Its clinical application for   periodontal diseases is highly valued.