Aliyah Olamide Ishola, Adam Mustapha, Ukpai A. Eze


Background:  Respiratory tract infection is a life-threatening infection in clinical medicine that affects both the upper and lower respiratory tract. Bacteria or viruses mainly cause them. Treating this infection involves using antibiotics to combat the bacterial, but the growing antimicrobial resistance hinders this process. The use of a natural substance called essential oils has been widely explored as it is said to possess both antibacterial and anti-viral properties. Therefore, a systematic review and meta-analysis was conducted to determine essential oils' anti-infective activity against respiratory bacterial related infections.

Main body: Databases of EBSCOhost, Google Scholar and Science Direct were used to search for related literature. This review included research on clinical trials and in vivo tests on bacterial related infection/diseases involving the use of essential oils published in English between 2000 – 2020, and excluded in vitro studies and studies published before 2000. A qualitative and quantitative analysis (forest plot & funnel plot) was conducted on collected data. Studies were retrieved by following the PRISMA guidelines, and the data extracted was analysed using the Mantel-Haenszel random effect model. A total of 11 eligible studies were identified, 7 clinical trials and 4 in vivo studies. Meta-analysis suggests a significant effect of essential oils on respiratory bacterial infections (OR = 5.09, 95% Cl = 2.30 – 11.28).

Conclusion: Overall, the qualitative and quantitative analysis suggests that essential oils possess antimicrobial activity, making it a promising futuristic approach in treating respiratory bacterial infections.


Respiratory bacterial infections; Essential oils; Antimicrobial agents; Natural products; Medicinal plants; Systematic literature review; Meta-analysis; Phytomedicine.

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