Methicillin-resistant Staphylococcus aureus (MRSA) is serious clinical urgent problems worldwide. In the present study, the antibacterial activity of Hylomecon hylomeconoides was investigated. The EtOH extract and its fraction (n-hexane, CH2Cl2, EtOAc, and H2O) were investigated against MRSA. The most active extract (CH2Cl2) led to the isolation of 6-methoxydihydrosanguinarine (6-MS), 6-acetonylhydrosanguinarine, and dihydrosanguinarine. These compounds were very active against MRSA strains with minimum inhibitory concentrations (MICs) ranging from 1.95 to 250 mu g/ml. Our study did however focus on 6-MS as it appeared to be the most active with MICs in the range of 1.9 to 3.9 mu g/ml. These results encourage us to think that 6-MS can be used as a natural antibacterial agent.