Abstract: OBJECTIVE To investigate the in vitro antibacterial activities of allitricin combined with different antibacterials against methicillin-resistant Staphylococcus aureus (MRSA), so as to provide references for clinical treatment. METHODS Thirty strains of MRSA were evaluated for susceptibilities to allitricin and other antibacterials respectively with broth dilution method. According to the minimal inhibitory concentration (MIC) of the two antimicrobials, activities of allitricin combined with other antibacterials against thirty strains of MRSA were evaluated by checkerboard synergy tests and the fraction inhibitory concentration (FIC) index was calculated. The antibacterial activities of allitricin combined with different antibacterials against MRSA were analyzed. RESULTS The MIC of allitricin to thirty strains of MRSA was 0.30±0.09 mg/mL. After combining with allitricin, the MIC₅₀ of oxacillin and cefazolin was decreased from 64 μg/mL, 32 μg/mL to 8 μg/mL, respectively, showing synergistic or additive effects. Meanwhile, the MIC₅₀ of vancomycin was reduced from 2 μg/mL to 0.5 μg/mL after the combination of allitricin, mainly demonstrating the additive effect. CONCLUSION The MRSA can be partly inhibited by allitricin, and an enhanced antibacterial effect was determined when allitricin was combined with other antibacterials. It is suggested that allitricin has a potential role of antibacterials sensitizing reagents in the treatment of serious infections due to MRSA, especially for vancomycin.