Garlic extract demonstrates antimicrobial efficacy comparable to other widely used antiseptics and disinfectants, such as chlorhexidine, according to University of Sharjah medical scientists.
Published in the Journal of Herbal Medicine , the study suggests that while garlic-based mouthwash may cause more discomfort than chlorhexidine, it offers longer-lasting residual effects.
"Chlorhexidine is widely used as a gold standard mouthwash but is associated with side effects and concerns over antimicrobial resistance," the authors note. "Garlic (Allium sativum), known for natural antimicrobial properties, has emerged as a potential alternative."
The findings are based on a systematic review of the literature in which the authors compare the antimicrobial efficacy of garlic extract with chlorhexidine in clinical practice, assessing its viability as a herbal substitute.
The study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses 2020 guidelines, which are specifically designed to enhance the credibility, completeness, and transparency of meta-analyses and systematic reviews. The paper also utilized the PICO framework, a structured approach that helps authors design clinical research questions to guide their systematic reviews.
"A total of 389 articles were identified from six electronic databases in January 2024, and an additional 13 articles were included through manual citation searching. After removing duplicates and applying inclusion and exclusion criteria, only five articles were included," the authors report.
The literature analyzed included randomized controlled trials and clinical studies, characterized by variable designs and low-to-moderate risks of bias. Findings indicate that higher concentrations of garlic extract mouthwash demonstrated antimicrobial efficacy comparable to chlorhexidine.
"The effectiveness varied based on mouthwash concentration and duration of application, contributing to differences in outcomes," the review revealed. "Some studies favored chlorhexidine for maintaining higher plaque/salivary pH, while others reported garlic extract to be more effective at certain concentrations. However, garlic mouthwash may cause greater discomfort."
Although garlic extract is not without side effects, they are generally less severe than those associated with chemical compounds. Reported adverse reactions include burning sensation and unpleasant odor, which may affect patients' willingness to replace chlorhexidine with garlic-based alternatives.
Despite these limitations, the review provides substantial evidence of garlic extract's clinical antimicrobial effectiveness, "with significant reductions in bacterial counts from baseline … suggesting the possible use of garlic extract mouthwash as a viable alternative to chlorhexidine in certain contexts."
The authors emphasize the need for further clinical research involving larger sample sizes and extended follow-up to confirm the "effectiveness and improve clinical applicability" of using garlic as an alternative mouthwash to the currently widely used chlorhexidine, which remains the gold standard antimicrobial mouthwash.
Research has established garlic as one of nature's most potent antibacterial and antifungal crops. For decades, scientists have sought to harness one of its compounds, called allicin, which exhibits strong antimicrobial properties. Although botanically classified as a vegetable, garlic is widely used both as a herb and a spice.
Global consumption of garlic reached approximately 30 million metric tons in 2024 , with China dominating both consumption and production, accounting for nearly 80% of the global supply. In the same year, the worldwide garlic extract market was valued at over $15 billion.
Garlic extracts have found applications in various health products and are available over-the-counter. In contrast, synthetic agents such as chlorhexidine typically require a prescription from a dentist or physician.
"Antimicrobial mouthwashes constitute an essential adjunct element in oral and dental care, acting against oral diseases caused by bacteria, fungi, or viruses attacking oral hard or soft tissues," according to the review. "Different antimicrobial mouthwashes, whether available over-the-counter or on prescription, can be used in the management of gingivitis, dental caries, periodontal diseases, halitosis, etc."
The review cites a host of studies demonstrating the antimicrobial activity of garlic extracts against numerous bacteria, fungi, and viruses. Additionally, it shows that garlic extracts have been investigated in different contexts, such as denture stomatitis, dentinal tubule disinfection, and as an intracanal medicament.
"These studies have contributed to understanding the antimicrobial role of garlic extract in comparison to synthetic agents like chlorhexidine," the authors note. "However, most studies are in vitro, vary in methods, and lack clinical standardization, highlighting the need for further research to confirm garlic's efficacy in dental practice. This uncertainty presents a significant gap in the literature on evidence-based antimicrobial therapies."
