The present study is designed to investigate the antibacterial effect of the hot-water and various ethanol extracts from the leaves of Dendropanax morbifera L. (DML) against Porphyromonas gingivalis (P. gingivalsis). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 30, 50 and 70% ethanol extract of DML against P. gingivalis decreased in a concentration-dependent manner. However, MIC and MBC of hot-water and 30% ethanol extract against P. gingivalis were the same as 3.13 and 6.25 mg/mL, respectively. In the bacterial growth inhibition test, the growth of P. gingivalis in the group treated with MBC and 2×MBC of DML hot-water extract was statistically significantly decreased from 6 h after incubation compared to the control group (p<0.001). From the results portrayed above, aqueous extract from DML at the concentration of 6.25 mg/mL can be usefully used to suppress infection of P. gingivalis, a major causative agent of periodontal disease.