This review discusses the antimicrobial activity of essential oils (EOs) against pathogenic bacteria. EOs, derived from plants, contain a variety of secondary metabolites that can inhibit or slow the growth of bacteria, yeasts, and molds. They target the cell membrane and cytoplasm, and in some cases, alter the morphology of cells. Gram-negative bacteria are generally more resistant to EOs than Gram-positive bacteria due to their complex cell wall structure, which includes an outer membrane (OM) that limits the penetration of hydrophobic molecules. However, EOs can still affect Gram-negative bacteria by disrupting the OM and altering membrane permeability. Terpenes and terpenoids are common components of EOs and have varying antimicrobial activities. For example, thymol and carvacrol are effective against Gram-positive bacteria, while p-cymene is less effective. The antimicrobial activity of EOs is influenced by their chemical composition, with some compounds, like trans-cinnamaldehyde, affecting both Gram-positive and Gram-negative bacteria. EOs can also affect the fatty acid profile of microbial membranes, altering membrane fluidity and permeability. Additionally, EOs can influence the expression of proteins involved in cell division, membrane transport, and energy metabolism, leading to cell death. The mechanisms of action of EOs include disrupting the cell membrane, altering membrane permeability, and affecting the production of ATP. Some EOs can also influence the quorum sensing systems of bacteria, which are crucial for bacterial communication and virulence. Overall, EOs exhibit a range of antimicrobial activities that can be attributed to their complex chemical composition and diverse mechanisms of action.This review discusses the antimicrobial activity of essential oils (EOs) against pathogenic bacteria. EOs, derived from plants, contain a variety of secondary metabolites that can inhibit or slow the growth of bacteria, yeasts, and molds. They target the cell membrane and cytoplasm, and in some cases, alter the morphology of cells. Gram-negative bacteria are generally more resistant to EOs than Gram-positive bacteria due to their complex cell wall structure, which includes an outer membrane (OM) that limits the penetration of hydrophobic molecules. However, EOs can still affect Gram-negative bacteria by disrupting the OM and altering membrane permeability. Terpenes and terpenoids are common components of EOs and have varying antimicrobial activities. For example, thymol and carvacrol are effective against Gram-positive bacteria, while p-cymene is less effective. The antimicrobial activity of EOs is influenced by their chemical composition, with some compounds, like trans-cinnamaldehyde, affecting both Gram-positive and Gram-negative bacteria. EOs can also affect the fatty acid profile of microbial membranes, altering membrane fluidity and permeability. Additionally, EOs can influence the expression of proteins involved in cell division, membrane transport, and energy metabolism, leading to cell death. The mechanisms of action of EOs include disrupting the cell membrane, altering membrane permeability, and affecting the production of ATP. Some EOs can also influence the quorum sensing systems of bacteria, which are crucial for bacterial communication and virulence. Overall, EOs exhibit a range of antimicrobial activities that can be attributed to their complex chemical composition and diverse mechanisms of action.