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<i>Pistacia lentiscus</i>, <i>Rosmarinus officinalis</i>, <i>Erica multiflora</i>, <i>Calicotome villosa</i>, and <i>Phillyrea latifolia</i> were considered important medicinal herbs and were used to treat various ailments. The present study was designed to evaluate the antioxidant and antimicrobial activities of ethanolic extracts (EEs). <i>P. lentiscus</i> and <i>R. officinalis</i> were the richest species in phenolic compounds. Similarly, both species showed the highest values of flavonoids. While the EEs of <i>P. lentiscus</i>, <i>E. multiflora</i>, and <i>C. villosa</i> had higher amounts of tannins. These phenolic compounds were evaluated by two different tests, namely diphenyl picrylhydrazyl (DPPH) and ferric iron-reducing power (FRAP). The IC₅₀ values were found to be significant <i>(p <</i> 0.05) for <i>P. lentiscus</i> and <i>E. multiflora</i>. Similarly, both plants showed the highest ferric-reducing antioxidant power (FRAP). This study has been conducted to evaluate the antibacterial potential of EEs against selected bacteria—Gram-positive bacteria (<i>Staphylococcus aureus</i> ATCC 29213, <i>Listeria monocytogenes</i> ATCC 7644) and Gram-negative bacteria (<i>Escherichia coli</i> ATCC 8739, <i>Salmonella typhimurium</i> NCTC 6017)—and determine their modes of action. The ethanolic extracts inhibited bacterial growth by producing concentration-dependent zones of inhibition. Treatment with these extracts at their minimum inhibitory concentrations (MICs) showed a significant reduction (<i>p <</i> 0.05) in the viability of bacteria. The extracts did not induce total lysis. Bacteria organisms treated with EEs at MICs showed a significant <i>(p <</i> 0.05) loss of tolerance to NaCl (5%). Our results highlighted the use of plant extracts as natural antibacterials that can be safely used in health care and led to the understanding of the antibacterial mechanism of plant extracts.