Antimicrobial, Calming, and Cholesterol-Lowering Properties

How lemongrass and its key compound citral fight pathogens, reduce anxiety, lower cholesterol, and ease inflammation

Lemongrass (Cymbopogon citratus) is a tropical grass used throughout Southeast Asia, India, and Latin America both as a culinary herb and a traditional medicine. Its distinctive citrusy aroma comes from citral — a potent bioactive aldehyde that makes up roughly 70–80% of its essential oil. Research has confirmed what traditional herbalists long observed: lemongrass has real antimicrobial, anti-inflammatory, and calming properties. It also shows meaningful cholesterol-lowering effects in human studies. [1][2] As a tea, seasoning, or supplemental extract, it is one of the more versatile medicinal herbs with a solid body of evidence behind its core uses.

How Lemongrass Works

The health effects of lemongrass trace primarily to its essential oil, which is dominated by two isomers of citral: geranial (also called citral-a, ~42% of the oil) and neral (citral-b, ~32%). These compounds are chemically reactive aldehydes that interfere with microbial membranes, modulate inflammatory signaling, and interact with olfactory receptors to produce calming effects. [2][6]

Beyond citral, lemongrass contains:

Myrcene — a monoterpene with analgesic and anti-inflammatory properties
Geraniol and nerol — antifungal and antibacterial alcohols
Quercetin, kaempferol, luteolin — flavonoids with antioxidant and anti-inflammatory effects
Isoorientin and chlorogenic acid — phenolics associated with blood sugar support [1]

This combination of terpenes and polyphenols means lemongrass works through multiple overlapping mechanisms simultaneously.

Antimicrobial Properties

Lemongrass essential oil has demonstrated broad-spectrum antimicrobial activity in laboratory settings. Against fungi, it inhibits Candida albicans, C. tropicalis, and Aspergillus niger with inhibition zone diameters of 35–90 mm. Against bacteria, it shows activity against both gram-positive organisms (Staphylococcus aureus, Bacillus subtilis) and gram-negative species (E. coli, Salmonella typhi). [6] The mechanism involves citral disrupting microbial cell membranes by embedding in the lipid bilayer, altering permeability and ultimately causing cell death.

It is worth noting that these are largely in vitro findings — test-tube concentrations of essential oil cannot be directly translated to what happens after drinking lemongrass tea. However, the antimicrobial properties are relevant for topical use (skin infections, oral health) and the oil is used clinically in some settings for this purpose. [2]

Anxiety and Nervous System Effects

A human study published in the Journal of Alternative and Complementary Medicine (n=40 male volunteers) found that inhaling lemongrass essential oil — even at a small dose of three to six drops — produced a significant reduction in state anxiety and subjective tension immediately after exposure, compared to both tea tree oil and distilled water controls. The effect appeared quickly and did not require repeated sessions. [3]

This aligns with traditional use of lemongrass tea as a calming beverage. The mechanism appears to involve citral interacting with GABA-A receptors in the brain — the same receptors targeted by benzodiazepines — though the effect is substantially milder. Animal studies confirm anxiolytic and mild sedative properties without toxicity at typical doses. [1]

Cholesterol and Cardiovascular Effects

A human clinical trial tested 140 mg/day of lemongrass essential oil (in capsule form) in 22 people with elevated cholesterol. Among the 8 subjects who responded to treatment, serum cholesterol fell by 25 mg/dl at 30 days, 33 mg/dl at 60 days, and 38 mg/dl at 90 days — reductions that would be clinically meaningful if replicated. [4] The non-responder/responder split (14 vs. 8) is not well understood but may reflect differences in baseline gut microbiome composition or genetic cholesterol metabolism.

Follow-up animal research confirmed that lemongrass essential oil reduces cholesterol without genotoxic or toxic effects after 21 days of oral intake, even at doses 10–100 times higher than the human study dose. [5] The proposed mechanism involves geraniol inhibiting hepatic HMG-CoA reductase — the same enzyme targeted by statin drugs — though the inhibition is far weaker.

Anti-Inflammatory Effects

Topically applied lemongrass essential oil significantly reduced paw edema in carrageenan-induced inflammation in animal models, with effects comparable to the reference anti-inflammatory drug at some doses. [2] In vitro, citral inhibits COX-2 enzyme expression and suppresses NF-κB signaling — key steps in the inflammatory cascade. These effects suggest lemongrass may help reduce low-grade chronic inflammation when used consistently, though human clinical trials for inflammation specifically are still lacking.

Practical Use

As a tea: Steep 1–2 stalks of fresh lemongrass (or 1–2 teaspoons of dried leaves) in hot water for 5–10 minutes. This is the most accessible and traditionally used preparation. Calming and digestive benefits are supported even through this mild preparation.

As a culinary herb: The lower stalk is edible and widely used in Thai, Vietnamese, and Indian cooking — soups, curries, stir-fries, marinades. Cooking preserves many of the phenolic antioxidants while the more volatile citral partially disperses.

As an essential oil: For topical antimicrobial or anti-inflammatory use, dilute in a carrier oil (2–3% concentration). For aromatherapy and anxiety, diffuse 3–6 drops in a room.

As a supplement: Standardized extracts in capsule form have been used at 140–500 mg/day in research settings. Less commonly available than the above forms but offers the most reliable dosing.

Lemongrass is well tolerated at food and tea doses. The essential oil should be diluted before topical use, as undiluted application can cause skin irritation. There are no well-documented drug interactions, but its mild cholesterol- and blood sugar-lowering effects mean people on statins or diabetes medications should be aware.

See our Hibiscus page for another plant-based tea with cardiovascular benefits, and our Ginger page for a related culinary herb with anti-inflammatory properties.

Evidence Review

Phytochemical Foundation

The 2011 review by Shah et al. [1] provides the foundational overview of lemongrass's chemical composition and pharmacological evidence base. The authors catalogued the major bioactive compounds — citral isomers (geranial and neral together comprising ~75% of the essential oil), geraniol, nerol, myrcene, and phenolic flavonoids including luteolin, isoorientin, quercetin, and kaempferol — and summarized evidence for antimicrobial, anti-inflammatory, antidiarrheal, and anxiolytic properties. The review notes that lemongrass is widely used in traditional systems of medicine across Southeast Asia, Africa, and South America, and that its safety profile is well established at culinary and tea doses.

Anti-inflammatory and Antifungal: Boukhatem et al. 2014

The most detailed in vivo anti-inflammatory study [2] characterized lemongrass essential oil's chemical profile (geranial 42.2%, neral 31.5% by gas chromatography-mass spectrometry) and tested its effects in two animal models: the carrageenan-induced paw edema model (oral and topical anti-inflammatory) and standard disc diffusion and broth microdilution assays (antifungal). Both oral and topical administration of lemongrass essential oil produced dose-dependent reductions in paw edema. Antifungal testing showed strong inhibition of Candida albicans, C. tropicalis, and Aspergillus niger in both liquid and vapor phases. The vapor-phase activity is notable because it suggests potential for environmental antimicrobial applications (diffuser use). This study is well-controlled but limited to animal models; no human anti-inflammatory trials exist to date.

Anxiety Reduction in Humans: Goes et al. 2015

The Goes et al. study [3] is one of the few human-controlled trials on lemongrass specifically. Forty healthy male volunteers were randomized to inhale lemongrass essential oil (3 drops), lemongrass essential oil (6 drops), tea tree oil (active control), or distilled water (placebo). After inhalation, all groups underwent a Stroop Color-Word Test — a validated stressor — and completed the State-Trait Anxiety Inventory (STAI) for state anxiety. Both lemongrass groups showed significantly reduced state anxiety and subjective tension immediately post-inhalation compared to both controls (p<0.05). Crucially, the anxiolytic effect did not persist to a 5-minute follow-up assessment, suggesting the effect is rapid but short-lived — appropriate for situational anxiety, not necessarily for ongoing anxiety management. The study is limited by its all-male sample, single-session design, and lack of physiological biomarkers. However, it provides direct human evidence for the traditional calming use.

Cholesterol Reduction: Elson et al. 1989 and Costa et al. 2011

The human cholesterol trial [4] remains underpowered by modern standards (n=22, no placebo control), but the effect size in responders is notable. Among the 8 responders, paired cholesterol reductions of 25, 33, and 38 mg/dl at 30, 60, and 90 days represent approximately 8–12% reductions from a baseline in the 315 mg/dl range — approaching what one might expect from low-dose statin treatment. The non-responder phenomenon (14 of 22 subjects showed no change) is unexplained and limits generalizability. The authors propose that genetic variation in HMG-CoA reductase activity may underlie the differential response.

The Costa et al. 2011 mouse study [5] addressed safety concerns directly. Mice received lemongrass essential oil at 1, 10, or 100 mg/kg for 21 days via oral gavage. No significant changes in body weight, organ weights, gross pathology, or histology were observed across any dose group. The comet assay (DNA strand break detection) showed no genotoxic effects. Total cholesterol was significantly reduced in all treatment groups versus controls. This safety profile at doses far exceeding likely human intake is reassuring.

Antimicrobial and Anticancer Review: Mukarram et al. 2022

This comprehensive review [6] synthesized evidence for lemongrass essential oil against bacteria, fungi, viruses, and cancer cell lines. Key antimicrobial findings: minimum inhibitory concentrations (MICs) for Candida species ranged from 0.019–0.15 mg/ml (comparable to some conventional antifungals), while bacterial MICs varied widely depending on species and oil composition. Anticancer activity was demonstrated in vitro for several cancer cell lines (HeLa, MCF-7, A549), with citral identified as the primary cytotoxic agent acting through mitochondrial membrane disruption and apoptosis induction. The authors note that anticancer evidence is entirely preclinical, and caution against over-interpretation — in vitro cytotoxicity does not predict clinical efficacy.

Evidence Strength Summary

The strongest evidence base covers antimicrobial properties (in vitro, multiple independent studies), anxiety reduction (one controlled human trial), and cholesterol lowering (one small human trial, replicated in animal models with safety data). Anti-inflammatory evidence is robust in animal models but lacks human trials. Anticancer evidence is preclinical only. Overall confidence: moderate for antimicrobial and calming effects; low-moderate for cholesterol reduction in humans; low for anti-inflammatory and anticancer effects pending human trials.

References

Scientific basis for the therapeutic use of Cymbopogon citratus, Stapf (Lemon grass)Shah G, Shri R, Panchal V, Sharma N, Singh B, Mann AS. Journal of Advanced Pharmaceutical Technology & Research, 2011. PubMed 22171285 →
Lemon grass (Cymbopogon citratus) essential oil as a potent anti-inflammatory and antifungal drugsBoukhatem MN, Ferhat MA, Kameli A, Saidi F, Kebir HT. Libyan Journal of Medicine, 2014. PubMed 25242268 →
Effect of Lemongrass Aroma on Experimental Anxiety in HumansGoes TC, Ursulino FR, Almeida-Souza TH, Alves PB, Teixeira-Silva F. Journal of Alternative and Complementary Medicine, 2015. PubMed 26366471 →
Impact of lemongrass oil, an essential oil, on serum cholesterolElson CE, Underbakke GL, Hanson P, Shrago E, Wainberg RH, Qureshi AA. Lipids, 1989. PubMed 2586227 →
Cholesterol reduction and lack of genotoxic or toxic effects in mice after repeated 21-day oral intake of lemongrass (Cymbopogon citratus) essential oilCosta CA, Bidinotto LT, Takahira RK, Salvadori DM, Barbisan LF, Costa M. Food and Chemical Toxicology, 2011. PubMed 21693164 →
Lemongrass Essential Oil Components with Antimicrobial and Anticancer ActivitiesMukarram M, Choudhary S, Khan MA, Poltronieri P, Khan MMA, Ali J, Kurjak D, Shahid M. Antioxidants, 2022. PubMed 35052524 →