Objective To study berberine on the activity of methicillin-resistant Staphylococcus aureus (MRSA) in vitro. Methods The size of antibacterial annulus, minimum inhibitory concentration (MIC) and minimum bactericidal concentration(MBC) of MRSA intervened by berberine were measured by Agar diffusion test and broth dilution test. The crystal violet staining method measured on 96 well Elisa-plate was applied to analyze minimal biofilm eradication concentration (MBEC). Results Compare with DMSO,berberine and chloramphenicol (positive control drug) could significantly increase the antibacterial annu...