Objective:Antibiotic resistance is the one of important problem in dental and medical fields. Therefore, new agents are needed to treat methicillin-resistant Staphylococcus aureus (MRSA) from acute oral infection. In the present study, we investigated the antimicrobial activity of Salvia miltiorrhiza (S. miltiorrhiza) and the antibacterial components, tanshinone IIA, tanshinone±and crytotanshinone from S. miltiorrhiza has been isolated and identified by MS, 1H-NMR, and 13C-NMR. Method:S. miltiorrhiza was extracted with 80% EtOH. The extract was suspended in H2O and partitioned with CHCl3, EtOAC, and n-BuOH in sequence. The CHCl3 fraction showed remarkable antibacterial activity against MRSA. Column chromatography of the most active fraction on silica gel and recycling prep-HPLC gave purified compounds. The structure of compounds was identified by MS, 1H-NMR, and 13C-NMR. Result:The CHCl3 fraction from solvent partition possessed greater antibacterial potential than other fractions. The fraction were obtained from column chromatography with silica gel had antibacterial activity against MRSA, and the fraction was separated by recycling prep-HPLC to purified compounds. Their structures were identified as tanshinone IIA, tanshinone± and crytotanshinone by MS, 1H-NMR, and 13C-NMR. The minimum inhibitory concentrations (MICs) of tanshinones to the S. aureus (MRSA and MSSA) ranged from 0.002 to 0.5 mg/ml. Conclusion:These results suggest that tanshinone IIA, tanshinone±and crytotanshinone might have the antibacterial activities against MRSA from acute oral infection. Supported by a grant of No. R01-2001-000-00133-0 from Korean Science & Engineering Foundation.