Benefits
Gum inflammation and tooth-surface cleaning with a lemongrass mouthwash
In small single-center trials, rinsing twice daily for three weeks with a 0.25% lemongrass essential oil mouthwash lowered gingival and tooth-deposit index scores, performing about as well as a chlorhexidine rinse in adults, orthodontic patients and children. These were short studies of a mouthwash used alongside normal brushing, not from drinking lemongrass tea.
Gum-pocket depth and breath odour in dental trials
In a trial of 40 adults with chronic gum disease, a 2% lemongrass gel placed in gum pockets after a professional cleaning reduced pocket depth, gum scores and bacterial counts over three months, comparably to a doxycycline gel. In a separate pilot of 20 volunteers, a lemongrass mouthrinse lowered the sulphur gases behind mouth odour. Both are rinse-and-spit dental uses.
Blood vessel relaxation in laboratory artery studies
Tested in vitro on rings of human artery in a tissue bath, a lemongrass leaf infusion produced a mild relaxation and dampened adrenaline-driven tightening, with tannins the most active fraction. In rats, lemongrass and citral relax vessels and briefly lower blood pressure. These are preliminary laboratory and animal findings; a human tea study found no change in blood cholesterol or triglycerides.
Calmer feelings when the aroma is inhaled
This research is about smelling lemongrass, not taking it by mouth. In 40 volunteers facing a stressful test, inhaling lemongrass essential oil briefly reduced reported tension and anxiety and sped recovery versus control aromas, and in dental patients inhaling the aroma during cleaning lowered anxiety scores. A human study of lemongrass tea found no calming or sleep effect when it was drunk.
Antioxidant plant compounds in laboratory tests
Lemongrass leaves contain citral and polyphenols such as luteolin, quercetin and isoorientin that scavenge free radicals and quench reactive oxygen species in test-tube assays. In a rat study, a lemongrass water extract raised blood antioxidant capacity and lowered lipid peroxidation. These are laboratory and animal measures of chemical activity, not shown to change antioxidant or disease outcomes in people who drink the tea.
Mechanism of action
Citral drives the aroma and much of the activity
Lemongrass essential oil is roughly two-thirds to four-fifths citral, a pair of closely related monoterpene aldehydes (geranial and neral). Citral is responsible for the lemon scent and for much of the antimicrobial and antioxidant activity seen in laboratory tests. The leaf and tea contain far less oil and more water-soluble polyphenols.
Antimicrobial action against mouth bacteria
In laboratory tests lemongrass oil and citral disrupt the membranes and biofilms of bacteria that drive dental plaque, gum inflammation and mouth odour, including Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. This is the proposed basis for the mouthwash and gel results, where the product acts on the surfaces of the mouth.
Vessel relaxation through nitric oxide and calcium channels
In isolated vessels and animal studies, lemongrass and citral are reported to relax vascular smooth muscle by promoting endothelial nitric oxide and prostanoid release and by blocking calcium entry into muscle cells; cyclooxygenase appears to take part in the relaxation of human artery segments. These mechanisms come from laboratory and animal work, not from trials in people.
Clinical trials
Double-blind, parallel three-arm clinical trial comparing a 0.25% lemongrass oil mouthwash, a 0.2% chlorhexidine mouthwash and oral prophylaxis alone over 21 days (Dany et al. 2015, J Clin Diagn Res).
60 subjects randomized into three groups of 20 after a professional cleaning set plaque scores to zero.
The lemongrass oil mouthwash group showed the largest reductions in gingival and plaque index scores at days 14 and 21, statistically significant (p less than or equal to 0.05). The authors concluded lemongrass oil mouthwash could serve as a herbal alternative to chlorhexidine, while calling for further study. A small single-center study of a rinse used with brushing.
Randomized three-arm study in fixed-orthodontic patients with gingivitis comparing a 0.25% lemongrass oil mouthwash, a 0.2% chlorhexidine mouthwash and oral prophylaxis for 21 days (Wasey et al. 2023, J Contemp Dent Pract).
60 patients undergoing fixed orthodontic treatment with mild-to-moderate gingivitis, 20 per group.
By days 14 and 21 the lemongrass oil group had lower plaque and gingival index scores, a significant difference versus the chlorhexidine group (p less than 0.001). The authors suggested lemongrass oil mouthwash as a possible herbal alternative to chlorhexidine. Small and single-center; a mouthwash used alongside brushing, not an oral supplement.
Double-blind, parallel-arm randomized controlled trial of a locally placed 2% lemongrass gel versus a 10% doxycycline hyclate gel as an adjunct to scaling and root planing (Mittal et al. 2022, Polymers).
40 adults with chronic periodontitis, 20 per group, followed at baseline, 1 month and 3 months.
Both gels gave significant reductions in gingival index, pocket depth, attachment level and counts of periodontal bacteria from baseline to 1 and 3 months (p less than 0.05), with the lemongrass gel comparable to the doxycycline gel. This is a gel placed in gum pockets during dental care, not something taken by mouth.
Laboratory antimicrobial testing plus a randomized double-blind pilot clinical study of a lemongrass oil mouthrinse for oral malodour, measuring volatile sulphur compounds on day 0 and day 8 (Satthanakul et al. 2015, J Appl Microbiol).
20 healthy volunteers in the clinical part.
The mouthrinse was active against odour-causing and gum-disease bacteria in the lab and significantly reduced volatile sulphur compounds, the gases behind mouth odour, by day 8. It appeared safe and acceptable, though the authors noted the spiciness and taste needed improvement. A small, short pilot of a rinse.
Double-blind, three-arm randomized clinical trial in severe periodontitis comparing a 0.25% lemongrass oil mouthwash, a 0.12% chlorhexidine mouthwash and oral prophylaxis, with blood markers measured before and 3 months after treatment (Subha et al. 2017, Ethiop J Health Sci).
45 adults with generalized severe periodontitis, 15 per group.
Within the lemongrass group, C-reactive protein, pocket depth, attachment loss, total cholesterol and LDL fell significantly from baseline. Between groups, only pocket depth and attachment loss differed significantly from the prophylaxis-only group; the lipid changes were within-group and not shown to beat the control. A small mouthwash study, not a test of swallowed lemongrass.
Early human study giving a lemongrass leaf tea to healthy volunteers as a single dose and as daily intake for two weeks, with blood and urine chemistry, EEG and EKG, plus double-blind tests of sleep and anxiety (Leite et al. 1986, J Ethnopharmacol).
Healthy volunteers for the chemistry and safety panel; 50 for the sleep test and 18 with high trait anxiety for the anxiety test.
The tea produced no change in serum glucose, cholesterol, triglycerides, lipids or liver and kidney markers, and EEG and EKG were normal; a few people had slight transient rises in direct bilirubin and amylase with no symptoms. It had no hypnotic or anxiolytic effect versus placebo. The authors concluded lemongrass tea is not toxic at these amounts but lacks sleep or anxiety effects when drunk.
Randomized human study assigning once-daily lemongrass leaf infusions prepared from 2, 4 or 8 g of leaf powder for 30 days, with renal function measured at days 0, 10 and 30 (Ekpenyong et al. 2015, J Ren Nutr).
105 adults aged 18 to 35 (55 men, 50 women).
Lower, shorter intake increased urine volume and frequency (a diuretic effect) without changing filtration at day 10. But by day 30, and at the 8 g dose sooner, creatinine clearance and estimated glomerular filtration rate fell and serum creatinine and urea rose. The authors reported dose- and time-dependent adverse effects on kidney filtration markers, a reason to keep to modest tea amounts.
Controlled human study in which volunteers inhaled lemongrass essential oil (3 or 6 drops), a tea-tree control aroma or water, then took a stressful color-word test, with psychological and physiological measures (Goes et al. 2015, J Altern Complement Med).
40 healthy male volunteers across four inhalation groups.
Those who inhaled lemongrass aroma, unlike the control groups, reported less state anxiety and tension right after inhaling and recovered fully within 5 minutes after the stressful task. Heart rate and muscle-activity changes during the test were not prevented by any treatment. The authors said the clinical relevance of the aroma needs more study. This tested smelling, not drinking, lemongrass.