The antimicrobial activity of EOs depends on their chemical constituents. Apparently, the antimicrobial activity of the EO analyzed is related to the presence of phenolic compounds (thymol) and terpene hydrocarbons (γ-terpinene), respectively [4,7,18]. p-Cymene, the third major element according to percentage, does not show antibacterial efficacy when used alone [7], synergistic effects being however attributed to it in relation to thymol and γ-terpinene, respectively [19,20], which might represent another cause of the antimicrobial activity recorded. On the other hand, a number of studies have shown that EOS exhibit stronger antimicrobial activity than that of their major constituents or their mixtures, respectively [21,22], which suggests synergistic effects of the minor components, but also the importance of all components in relation to the biological activity of EOs.