Being consumed as a spice, Origanum species are also utilized for alternative medical treatment and are therefore of great economic importance. This study examined the effect of Origanum vulgare L. subsp. gracile (OVG) essential oil (EO) against planktonic cell growth and biofilm formation of cariogenic Streptococcus mutansas well as its cytotoxic activity. The antimicrobial potential of EO was screened by broth microdilution method