Biofilm formation and hemolysis are closely related to the pathogenicity of . Strategies that reduce the mortality of infections may involve novel antimicrobials and/or drugs that decrease virulence, such as biofilm formation. The antiviral drug efavirenz is a non-nucleoside reverse transcriptase inhibitor, which also has shown antibacterial effect on and . Its effect on pathogen virulence has not yet been explored. This study investigates the antimicrobial and anti-virulence effect of efavirenz on . Biofilm biomasses were detected by crystal violet staining. Hemolysis activities of were determined by rabbit erythrocytes lysis assay. RNA levels of transcriptional regulatory genes, biofilm-related genes, and virulence-related genes of were determined by RT-qPCR. Efavirenz showed an inhibitory effect on the growth of , and at 50 µM. Efavirenz significantly inhibited biofilm formation of both methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) at 25 µM, but did not affect the growth of planktonic cells. Moreover, hemolysis by was inhibited by efavirenz at 25 µM. The expression levels of RNA transcriptional regulatory genes (, , , and ), biofilm-related genes (, , , , ), and virulence-related genes (, , , , ) of decreased significantly at 25 µM efavirenz. Efavirenz inhibits biofilm formation and virulence .