Lemongrass field with healthy teeth

Unlocking Nature's Power: Can Lemongrass Combat Dental Biofilm?

Nico Varela monogram
Nico Varela in Health & Wellness October 2026 • 4 min read.

"Explore the potential of lemongrass essential oil in fighting Streptococcus mutans biofilms, offering a natural approach to dental health."


Dental caries, commonly known as tooth decay, affects a significant portion of the global population. Characterized by an imbalance between demineralization and remineralization processes in the mouth, dental caries remains a widespread health concern. The World Health Organization (WHO) reports that the prevalence of caries in school children ranges from 60% to 90%, highlighting the urgent need for effective preventive strategies.

Streptococcus mutans, a key player in the development of dental caries, is known for its ability to produce organic acids that dissolve tooth enamel, leading to cavities. Traditional approaches to caries prevention include measures such as dental plaque control, dietary modifications, and topical fluoride applications. However, challenges such as unequal access to fluoridated water and potential adverse effects associated with chemical interventions underscore the importance of exploring alternative solutions.

In recent years, research into natural extracts has gained momentum due to their potential as novel pharmacological agents for preventing and treating various oral pathologies. Among these natural extracts, medicinal plants like Cymbopogon citratus, commonly known as lemongrass, have garnered attention for their antimicrobial properties.

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How Plaque Contributes to Tooth Decay

The World Health Organization explains that dental caries can develop when plaque forms on a tooth’s surface. Bacteria in the plaque convert free sugars in foods and drinks into acids. Those acids destroy tooth structure over time.

Plaque Management and Lemongrass Mouthwash Research

A study published on January 7, 2022, set out to assess the antimicrobial and anti-biofilm properties of a mouthwash based on lemongrass essential oil (LGEO) against microbial flora from dental plaque. A review describes lemongrass, or Cymbopogon citratus, as a Poaceae grass and reports that its antibacterial and antimicrobial qualities have prompted interest in medical and dental applications. The supplied source material does not specify standard-care methods or establish that lemongrass mouthwash is an accepted replacement for them.

Lemongrass Oil and Oral Health Research

A review identifies lemongrass as Cymbopogon citratus, a member of the Poaceae grass family, and discusses its potential dental applications. A reported randomized controlled trial examined lemon grass essential oil for oral thrush in an HIV-positive population. Another source says lemongrass essential oil has been used for decades for a range of conditions, including respiratory and sinus infections, but the supplied material does not date the start of its use for oral health.

Why Lemongrass Essential Oil Could Be Your New Dental Ally

Lemongrass field with healthy teeth

A recent study published in the African Journal of Microbiology Research investigated the effects of lemongrass essential oil (LGO) on Streptococcus mutans biofilms. The study aimed to determine whether LGO could inhibit the growth and development of these biofilms, which contribute significantly to dental caries.

The researchers conducted several experiments to assess the antimicrobial activity of LGO. They first evaluated the susceptibility of planktonic S. mutans cells to LGO using the inhibition zone test and minimum inhibitory concentration (MIC) assay. Subsequently, they investigated the impact of LGO on S. mutans biofilms formed on hydroxyapatite discs, which mimic the tooth surface.

  • Inhibition Zone Test: This test assesses the ability of a substance to prevent bacterial growth on an agar plate. A clear zone around the substance indicates its antimicrobial activity.
  • Minimum Inhibitory Concentration (MIC) Assay: The MIC is the lowest concentration of a substance required to inhibit the visible growth of a microorganism.
  • Biofilm Formation Assay: This experiment involves growing bacterial biofilms on a surface (in this case, hydroxyapatite discs) and then treating them with the substance being tested. The effectiveness of the substance is determined by measuring the reduction in biofilm formation.
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Evidence and Exposure-Time Caveats

A systematic review reports that 88% of the current evidence on essential oils’ anti-caries potential comes from in vitro studies rather than clinical trials. Another source cautions that anticaries potential should not be inferred without testing antibiofilm activity using more clinically relevant brief exposures. A study’s cytotoxicity results were based on 24-hour treatments, whereas the recommended mouthwash use cited in that source is about two minutes. It therefore notes that the longer exposure was intended to identify residual tissue effects and does not by itself establish effects under typical rinsing conditions.

Chlorhexidine Evidence and a Lemongrass Trial

A Cochrane summary reports that, at four to six weeks, plaque scores were lower with chlorhexidine mouthrinse by 1.45 standard deviations (95% CI 1.00 to 1.90), based on 12 trials with 950 participants and high-quality evidence. A separate study compared 0.25% lemongrass oil mouthwash with 0.2% chlorhexidine in children. Its supplied snippet reports a baseline plaque pH of 7.59 in children aged 8–12, attributed to a cited study by Muralikrishnan et al. The provided material does not give the comparative trial’s results, so it does not support a claim that either rinse was superior in that study.

The results of the study revealed that LGO exhibited promising antimicrobial activity against S. mutans biofilms. The susceptibility test showed positive results, indicating that LGO inhibited the growth of microorganisms. The MIC value was determined to be 0.04 mg/mL, suggesting that even low concentrations of LGO can effectively inhibit bacterial growth. Furthermore, the biofilm results demonstrated that LGO significantly decreased bacterial growth in comparison to the control group.

Embrace the Natural Route to a Healthier Smile

The findings of this study suggest that lemongrass essential oil holds great potential as a natural agent for controlling bacterial growth in Streptococcus mutans biofilms. By incorporating lemongrass essential oil into your oral hygiene routine, you can take a proactive approach to maintaining healthy teeth and gums. Remember to consult with your dentist or healthcare provider before making any significant changes to your oral care regimen. Together, you can explore the best strategies for achieving a brighter, healthier smile!

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What the LGEO Mouthwash Study Set Out to Test

A study of lemongrass essential oil (LGEO)-based mouthwash describes mouthwash as a convenient method for dental plaque management. Its stated aim was to investigate the formulation’s antimicrobial and anti-biofilm properties against microbial flora from dental plaque. The study also set out to check the formulation’s cytotoxicity. The supplied source describes these research aims but does not provide findings that establish clinical effectiveness or safety.

Investigating Lemongrass Oil’s Effects on P. gingivalis

A December 13, 2025, report titled “Lemongrass Oil Diminishes Porphyromonas gingivalis Activity” describes a study highlighting multitarget inhibitory effects of lemongrass essential oil. The report presents these effects as relevant to dental care and to understanding links between oral health and overall well-being. The supplied snippet does not give methods, results, or clinical evidence, so it does not establish how the findings may translate into dental treatment.

Lemongrass oil's effect in biofilm tests

  • 3.55 log UFC/mLIn microcosm biofilms, combining C. citratus oil with chlorhexidine reduced total bacterial counts and aciduric bacteria, with a maximum reduction of 3.55 log UFC/mL.[1]

How the evidence compares across biofilm models

The oil-alone result involved viable cells of lactobacilli and streptococci in biofilms, while the combination result measured total bacterial counts and aciduric bacteria in microcosm biofilms. These outcomes describe different bacterial measures and cannot be treated as a direct comparison of the treatments.[1] [2]

A microcosm model brings interactions among different microorganisms into the experiment, making it relevant to the ecological complexity of oral biofilms; it remains a model rather than a clinical outcome.[1]

Across essential-oil research on anticaries potential, most of the evidence is from in vitro work rather than clinical trials. That broader evidence base places these biofilm findings in a preclinical context.[3]

What remains uncertain about lemongrass biofilm effects

  • Would the reduction in viable biofilm cells persist under conditions that better reflect oral biofilms and their interactions? The cited work describes both a polymicrobial model and the need for clinical confirmation, but does not settle that question.[1] [2]

Sources

  1. Cymbopogon citratus Essential Oil Increases the Effect of Digluconate Chlorhexidine on Microcosm Biofilms (pmc.ncbi.nlm.nih.gov)
  2. Cymbopogon citratus essential oil: effect on polymicrobial caries-related biofilm with low cytotoxicity. (pubmed.ncbi.nlm.nih.gov)
  3. Antibacterial Activity of Essential Oils and Their Isolated Constituents against Cariogenic Bacteria: A Systematic Review (pmc.ncbi.nlm.nih.gov)

About this Article -

Written with AI assistance from published research, and reviewed by the Mystum team. See our About page for more information.

Everything You Need To Know

1

What exactly causes tooth decay and what are the traditional ways to prevent it?

Dental caries, commonly known as tooth decay, arises from an imbalance between demineralization and remineralization processes in the mouth. This condition is largely influenced by the bacteria Streptococcus mutans, which produces organic acids that erode tooth enamel. Effective prevention involves dental plaque control, dietary adjustments, and fluoride treatments. However, due to challenges such as unequal access to fluoridated water and concerns about chemical interventions, alternative solutions are being explored.

2

Why is Streptococcus mutans so important when we talk about cavities?

Streptococcus mutans is significant because it is a primary bacterium responsible for the formation of dental caries. This bacterium produces organic acids that dissolve tooth enamel, leading to cavities. Controlling the growth and activity of Streptococcus mutans is crucial in preventing tooth decay and maintaining oral health. This control can be achieved through various methods, including the use of antimicrobial agents like lemongrass essential oil.

3

How does lemongrass essential oil work to help with dental health?

Lemongrass essential oil (LGO) shows promise as a natural agent against Streptococcus mutans biofilms due to its antimicrobial properties. Studies have demonstrated that LGO can inhibit the growth and development of these biofilms, which significantly contribute to dental caries. The effectiveness of LGO is evaluated through tests like the inhibition zone test, which assesses its ability to prevent bacterial growth, and the minimum inhibitory concentration (MIC) assay, which determines the lowest concentration needed to inhibit bacterial growth. The biofilm formation assay further confirms LGO's ability to reduce bacterial growth on tooth-like surfaces.

4

What is an inhibition zone test and why is it important in testing natural remedies?

The inhibition zone test is used to assess the antimicrobial activity of a substance, such as lemongrass essential oil. In this test, a substance is placed on an agar plate inoculated with bacteria. If the substance inhibits bacterial growth, a clear zone appears around it. This test provides a visual indication of the substance's ability to prevent bacterial growth. The minimum inhibitory concentration (MIC) assay is then used to find the lowest concentration of the substance required to inhibit visible growth of a microorganism.

5

Does this mean I should start using lemongrass oil instead of brushing my teeth?

While lemongrass essential oil shows potential in combating Streptococcus mutans biofilms, it's important to note that this research is a starting point. The study focuses on in vitro results, and further clinical trials are needed to fully understand its effectiveness and safety in humans. Aspects such as the optimal concentration, method of application, and long-term effects still need to be investigated. Additionally, the study does not cover other potential benefits or drawbacks of using lemongrass essential oil in oral hygiene, such as its impact on other oral bacteria or potential interactions with other dental products.

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