1 In general, gas chromatography–mass spectrometry (CG‐MS) is used to determine the chemical composition of EOs. They are secreted in special cells, in secretion ducts or cavities or in glandular hairs from which they are extracted by distillation (water‐steam or hydro‐distillation), pressing, enfleurage, solvents or by supercritical fluid extraction. Copyright © 2015 John Wiley & Sons, Ltd.Įssential oils (EOs) are the mixture of volatile compounds, mainly mono‐ and sesquiterpenoids, phenylpropanoids, etc., containing hundreds of individual chemical constituents, which may have biological activity. On the whole, this review aimed at showing EOs as potential antimicrobials and as anti‐inflammatory agents to alleviate symptoms and signs of RTDs including RTIs. Patents deal with the role of EOs and their volatile constituents in the treatment of RTIs are also introduced. Results coming from recently performed in vivo animal studies as well as human trials are also reported. The mode of action of EOs on bacterial cells and their anti‐inflammatory action are also discussed. The purpose of this review is to describe the most frequently developing infections of the upper and lower respiratory tract and to show methods used for the determination of the antibacterial activity of EOs by gaseous contact. Moreover, due to their antimicrobial and anti‐inflammatory potency, they offer an effective treatment in respiratory tract infections (RTIs). Because of volatility, EOs can easily reach the upper and lower parts of the respiratory tract via inhalation. Respiratory tract diseases (RTDs) associated with bacterial infection and inflammation affect a large number of people from every age group worldwide. EOs have a complex mode of action due to their multiple composition. The investigation of the antibacterial effect of essential oils (EOs), which are commonly used nowadays in cosmetics, health care, traditional medicine and food industry, could be one of the promising solutions for this worldwide problem. The appearance of multidrug resistant bacteria and growing antibiotic resistance is leading to a continuous need for discovering new drugs and alternative treatments against infections.

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