Lemongrass — Benefits Deep Dive

Lemongrass (Cymbopogon citratus) is one of the few plants that is simultaneously a kitchen staple, a household beverage and a laboratory workhorse. The stalk flavors a pot of tom yum; the dried leaves make a mild, faintly sweet lemon tea drunk by the mugful from Brazil to Bangkok; and the steam-distilled essential oil — often 70–85% citral — is one of the most-tested antimicrobial plant oils in the published literature. These four pages take each of the plant's four best-documented claim areas in turn and ask a deliberately narrow question of every one: what was actually given, to whom, and what actually changed?

Before you read any further, hold on to the single distinction that governs this whole section. Lemongrass tea and lemongrass essential oil are not two strengths of the same product. A cup of infusion delivers water-soluble flavonoids and a trace of volatile citral, and it has a long, boring, reassuring safety record — the one human trial that specifically hunted for toxicity from the tea found none. A bottle of essential oil is a concentrated distillate that irritates skin, is a recognized cause of contact allergy, and must never be swallowed. The great majority of the impressive antimicrobial numbers you will see quoted online come from the oil in a petri dish. Nothing about those numbers transfers automatically to a teapot, and this section will say so every time the distinction matters.

The second thing to hold on to is the evidence tier. Every claim on these pages is labeled one of four ways: randomized clinical trial (tested in people, with a control group), preliminary human (small, uncontrolled or single-arm work in people), preliminary (animal, isolated-tissue or in-vitro only) and traditional use only (a real, documented folk practice with no supporting trial). Lemongrass has a great deal in the third and fourth categories, a little in the second, and almost nothing in the first. That is not a criticism of the plant — it is an accurate description of a well-loved food that has never had a reason to attract pharmaceutical-scale funding. Read it that way and lemongrass becomes genuinely useful: a delicious flavor, a low-risk daily beverage, an interesting oil for topical and household use, and not a medicine.

Table of Contents

1. Deep-Dive Articles
2. Tea, Stalk and Oil: Three Different Products
3. How to Read the Evidence Tiers
4. Key Research — Digestion and Cramping
5. Key Research — Anxiety, Sleep and Aroma
6. Key Research — Antimicrobial and Oral Health
7. Key Research — Lipids and Metabolism
8. Key Research — Safety, Citral and Pregnancy
9. External Resources
10. Connections

Deep-Dive Articles

Four articles, each one claim area, each one honest about which tier its evidence sits in.

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Tea, Stalk and Oil: Three Different Products

Almost every confused claim about lemongrass comes from silently swapping one of these three for another. They are worth separating explicitly, because their exposures differ by orders of magnitude.

The stalk, as food

The pale lower stalk, bruised whole in a broth or minced into a curry paste, is a culinary ingredient. The amount of citral that reaches you is small and diluted through a shared dish. There is no meaningful safety question here beyond ordinary food allergy, and there is also no plausible pharmacology — nobody has ever shown a therapeutic effect from lemongrass as an ingredient in soup, and it would be surprising if they did.

The leaf infusion, as tea

A tea made by steeping fresh or dried leaves for five to ten minutes extracts the water-soluble fraction: flavonoids including luteolin and apigenin derivatives, other polyphenols, tannins and a modest amount of volatile citral that carries over in the steam and the aroma. This is the form with the folk-medicine reputation, and — importantly — it is the form used in the small number of studies that actually gave lemongrass to people by mouth. Its safety record is good. Its measured effects are modest to absent.

The essential oil, as a concentrate

Steam distillation of the leaves yields an oil that is mostly citral (geranial plus neral), with geraniol, citronellal, limonene, myrcene and geranyl acetate making up most of the rest. This is a different product with a different risk profile:

• Never swallow it. Concentrated essential oils are not foods and the dose in a single teaspoon is nothing like a cup of tea.
• Dilute it for skin. Neat lemongrass oil irritates skin and is a documented contact allergen; the standard practice is dilution in a carrier oil plus a patch test.
• It is the oil, not the tea, that produced the antimicrobial literature. When you read that lemongrass "kills MRSA," the experiment was oil against bacteria on a plate.
• Keep it away from small children, cats and dogs, for whom concentrated essential oils are a genuine hazard.

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How to Read the Evidence Tiers

These four labels appear throughout the sub-articles. They are not decoration — the gap between the first and the last is the difference between a treatment and a habit.

1. Randomized clinical trial. People, randomly assigned, with a comparison group. For lemongrass this tier is nearly empty: a randomized human study of lemongrass aroma and experimental anxiety, and small dental and dermatological studies with control arms. Nothing large, nothing long.
2. Preliminary human. Small, single-arm or uncontrolled work in people — the oral thrush study, the early cholesterol study, the 1986 tea trial (which was controlled but small and negative). Useful for safety signals and for generating hypotheses; not sufficient to establish benefit.
3. Preliminary (animal, tissue or in-vitro). The bulk of the lemongrass literature. Rats, mice, isolated rabbit ileum, cultured cells, agar plates. This tier tells you a mechanism could exist. It does not tell you what happens in a person drinking tea, because dose, absorption, first-pass metabolism and dilution all intervene.
4. Traditional use only. Documented, sometimes centuries-old practice with no supporting trial — the Caribbean "fever grass" tea for colds, the Brazilian bedtime capim-santo. Worth recording faithfully. Not evidence of effect.

One more habit worth borrowing: when an in-vitro concentration is quoted, ask whether a human body could ever reach it. Antimicrobial minimum inhibitory concentrations for essential oils are frequently in the range of hundreds to thousands of micrograms per milliliter — concentrations that are easy to create in a well and impossible to create safely in blood. That single question dissolves most of the exaggerated claims about this plant.

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Key Research — Digestion and Cramping

1. Preliminary (isolated tissue). Devi RC, Sim SM, Ismail R. Spasmolytic effect of citral and extracts of Cymbopogon citratus on isolated rabbit ileum. Journal of Smooth Muscle Research, 2011. Find on PubMed — the mechanistic anchor for the antispasmodic claim: citral relaxed contracted intestinal smooth muscle in an isolated-organ bath.
2. Preliminary (animal). Sagradas J, Costa G, Figueirinha A, et al. Gastroprotective effect of Cymbopogon citratus infusion on acute ethanol-induced gastric lesions in rats. Journal of Ethnopharmacology, 2015. Find on PubMed — notable because it tested the infusion, the form people actually drink.
3. Preliminary (cell culture). Figueirinha A, Cruz MT, Francisco V, Lopes MC, Batista MT. Anti-inflammatory activity of Cymbopogon citratus leaf infusion in lipopolysaccharide-stimulated dendritic cells. Journal of Medicinal Food, 2010. Find on PubMed — attributes part of the infusion's activity to its polyphenols rather than to citral.
4. Preliminary (animal). Carbajal D, Casaco A, Arruzazabala L, Gonzalez R, Tolon Z. Pharmacological study of Cymbopogon citratus leaves. Journal of Ethnopharmacology, 1989. Find on PubMed — an early broad screen covering analgesic, anti-inflammatory and smooth-muscle effects.
5. Context — randomized trials, different herb. Khanna R, MacDonald JK, Levesque BG. Peppermint oil for the treatment of irritable bowel syndrome: a systematic review and meta-analysis. Journal of Clinical Gastroenterology, 2014. Find on PubMed — included as the benchmark: this is what a properly evidenced botanical antispasmodic looks like, and lemongrass has nothing comparable.

Key Research — Anxiety, Sleep and Aroma

1. Randomized clinical trial (aroma). Goes TC, Ursulino FR, Almeida-Souza TH, Alves PB, Teixeira-Silva F. Effect of lemongrass aroma on experimental anxiety in humans. Journal of Alternative and Complementary Medicine, 2015. Find on PubMed — the strongest single human result on the plant, and it is about smelling it, not drinking it.
2. Preliminary human (negative). Leite JR, Seabra ML, Maluf E, et al. Pharmacology of lemongrass (Cymbopogon citratus Stapf). III. Assessment of eventual toxic, hypnotic and anxiolytic effects on humans. Journal of Ethnopharmacology, 1986. Find on PubMed — the tea produced no measurable anxiolytic or hypnotic effect, and no toxicity either. Both halves of that sentence matter.
3. Preliminary (animal). Costa CA, Kohn DO, de Lima VM, Gargano AC, Flório JC, Costa M. The GABAergic system contributes to the anxiolytic-like effect of essential oil from Cymbopogon citratus (lemongrass). Journal of Ethnopharmacology, 2011. Find on PubMed — mice, and a plausible mechanism.
4. Preliminary (animal). Blanco MM, Costa CA, Freire AO, Santos JG Jr, Costa M. Neurobehavioral effect of essential oil of Cymbopogon citratus in mice. Phytomedicine, 2009. Find on PubMed
5. Context — systematic review. Aromatherapy and sleep quality have been reviewed across many oils and populations. PubMed topic search: aromatherapy and sleep quality — useful for judging how much of any inhaled-aroma benefit is oil-specific and how much is the ritual.

Key Research — Antimicrobial and Oral Health

1. Preliminary (in vitro). Naik MI, Fomda BA, Jaykumar E, Bhat JA. Antibacterial activity of lemongrass (Cymbopogon citratus) oil against some selected pathogenic bacteria. Asian Pacific Journal of Tropical Medicine, 2010. Find on PubMed
2. Preliminary (in vitro). Silva CB, Guterres SS, Weisheimer V, Schapoval EE. Antifungal activity of the lemongrass oil and citral against Candida spp. Brazilian Journal of Infectious Diseases, 2008. Find on PubMed
3. Preliminary (in vitro). Boukhatem MN, Ferhat MA, Kameli A, Saidi F, Kebir HT. Lemon grass (Cymbopogon citratus) essential oil as a potent anti-inflammatory and antifungal drug. Libyan Journal of Medicine, 2014. Find on PubMed
4. Preliminary human. Wright SC, Maree JE, Sibanyoni M. Treatment of oral thrush in HIV/AIDS patients with lemon juice and lemon grass (Cymbopogon citratus) and gentian violet. Phytomedicine, 2009. Find on PubMed — a topical oral application, not a swallowed dose.
5. Preliminary human (controlled). Chaisripipat W, Lourith N, Kanlayavattanakul M. Anti-dandruff hair tonic containing lemongrass (Cymbopogon flexuosus) oil. Complementary Medicine Research, 2015. Find on PubMed — note the species: C. flexuosus, East Indian lemongrass, not the culinary C. citratus.
6. Preliminary human (small clinical study). A three-arm study of a 0.25% lemongrass oil mouthwash against chlorhexidine and a control was reported in the Journal of Clinical and Diagnostic Research, 2015. PubMed topic search: lemongrass oil mouthwash
7. Preliminary (in vitro). PubMed topic search: Cymbopogon citratus and Streptococcus mutans biofilm — the dental-plaque organism, tested on plates and in biofilm models.

Key Research — Lipids and Metabolism

1. Preliminary human. Elson CE, Underbakke GL, Hanson P, Shrago E, Wainberg RH, Qureshi AA. Impact of lemongrass oil, an essential oil, on serum cholesterol. Lipids, 1989. Find on PubMed — the origin of essentially every "lemongrass lowers cholesterol" headline. Small, mixed, and never replicated at scale.
2. Preliminary (animal). Adeneye AA, Agbaje EO. Hypoglycemic and hypolipidemic effects of fresh leaf aqueous extract of Cymbopogon citratus Stapf. in rats. Journal of Ethnopharmacology, 2007. Find on PubMed
3. Preliminary (isolated tissue). Devi RC, Sim SM, Ismail R. Effect of Cymbopogon citratus and citral on vascular smooth muscle of the isolated thoracic rat aorta. Evidence-Based Complementary and Alternative Medicine, 2012. Find on PubMed — the vasorelaxation finding behind the blood-pressure claim.
4. Preliminary (in vitro). Cheel J, Theoduloz C, Rodríguez J, Schmeda-Hirschmann G. Free radical scavengers and antioxidants from lemongrass (Cymbopogon citratus (DC.) Stapf.). Journal of Agricultural and Food Chemistry, 2005. Find on PubMed
5. Preliminary human. A small study of daily lemongrass tea consumption and kidney filtration markers was reported in the Journal of Renal Nutrition, 2015. PubMed topic search: lemongrass tea and glomerular filtration

Key Research — Safety, Citral and Pregnancy

1. Preliminary human (safety). Leite JR, et al., 1986, above — the same trial that found no anxiolytic effect also found no toxicity from the tea, including no changes in the liver and blood panels checked.
2. Preliminary (animal, reproductive). Souza Formigoni ML, Lodder HM, Gianotti Filho O, Ferreira TM, Carlini EA. Pharmacology of lemongrass (Cymbopogon citratus Stapf). II. Effects of daily two-month administration in male and female rats and in offspring exposed in utero. Journal of Ethnopharmacology, 1986. Find on PubMed — the most directly relevant animal reproductive-exposure work.
3. Preliminary (animal, high-dose citral). Repeated high-dose citral exposure has been reported to induce prostatic hyperplasia in rats, attributed to an estrogen-like action. PubMed topic search: citral and prostatic hyperplasia — a reason to be cautious with concentrated citral, not with a cup of tea.
4. Review (skin safety). de Groot A, Schmidt E. Essential oils, part V: peppermint oil, lavender oil, and lemongrass oil. Dermatitis, 2016. Find on PubMed — the contact-allergy and irritation record for the oil.
5. Reviews (overall). Shah G, Shri R, Panchal V, Sharma N, Singh B, Mann AS. Scientific basis for the therapeutic use of Cymbopogon citratus, Stapf (lemon grass). Journal of Advanced Pharmaceutical Technology & Research, 2011. Find on PubMed · Ekpenyong CE, Akpan E, Nyoh A. Ethnopharmacology, phytochemistry, and biological activities of Cymbopogon citratus (DC.) Stapf extracts. Chinese Journal of Natural Medicines, 2015. Find on PubMed

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External Resources

• PubMed — all Cymbopogon citratus literature — the whole file, roughly a thousand records, overwhelmingly preclinical.
• PubChem — citral — chemistry, hazard classification and toxicology summaries for the plant's principal constituent.
• NCCIH — Herbs at a Glance — the US National Center for Complementary and Integrative Health's plain-language evidence summaries.
• Memorial Sloan Kettering — About Herbs — conservative, referenced monographs including lemongrass, with interaction notes.
• LiverTox (NIH) — the reference database for herbal and dietary supplement liver injury.
• USDA FoodData Central — nutrient composition for lemongrass as a food.
• Plants of the World Online (Kew) — botanical authority for the Cymbopogon genus, useful for untangling C. citratus, C. flexuosus, C. nardus and C. winterianus.

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Connections

• All Herbs
• Lemongrass — the main topic page: botany, culinary use, compounds and safety.
• Peppermint Benefits — the properly evidenced botanical antispasmodic to compare lemongrass against.
• Lemon Balm Benefits — the other lemony calming herb, with better human trial data.
• Chamomile Benefits — the archetypal bedtime tea and its apigenin story.
• Ginger Benefits — lemongrass's constant kitchen partner, and a genuinely trial-tested anti-nausea herb.
• Fennel Benefits — a classic carminative for bloating and gas.
• Lavender Benefits — the most-studied aromatherapy oil, a useful yardstick for inhaled-aroma claims.
• Tea Tree — another topical antimicrobial essential oil with the same tea-versus-oil confusion.
• Aromatherapy — how inhaled-aroma studies are designed and where they fall down.
• Luteolin — a flavonoid found in lemongrass leaf infusion.
• Apigenin — the other major flavonoid in the leaf, shared with chamomile.
• Irritable Bowel Syndrome — the condition most often self-treated with carminative teas.
• Anxiety — where the aroma evidence would apply if it scaled.
• Cholesterol Management — what actually moves lipid numbers.
• Gingivitis — the target of the lemongrass mouthwash work.
• Galangal — a Southeast Asian aromatic that shares the same dishes.
• Kaffir Lime — the third leg of the tom yum aromatic trio.

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