Elephant's Foot (Elephantopus scaber)

Elephant's foot is a flat rosette weed of roadsides and open ground across Vietnam, Indonesia, Malaysia, southern China, India and the Philippines, where it has been used for centuries against fever, liver complaints, boils and wounds. Over the last two decades it has attracted serious laboratory attention for a very specific reason: one of its constituents, deoxyelephantopin, kills cancer cells in culture at low concentrations and shrinks tumours in mice. That literature is substantial and it is real.

It is also entirely in vitro and rodent. No human clinical trial of this plant or of deoxyelephantopin exists. We could not locate human clinical evidence for any indication — not cancer, not fever, not liver disease. That gap is the single most important thing on this page, because the cell-line results are striking enough that they are already being sold as though they meant something clinically, and they do not yet.

There is a second warning that belongs at the top rather than buried at the bottom. The molecules responsible for the interesting activity are sesquiterpene lactones, and sesquiterpene lactones are one of the best-documented classes of plant contact allergen in dermatology. This is an Asteraceae plant, so anyone sensitised to ragweed, chrysanthemum, feverfew or arnica should expect cross-reactivity. The chemistry that makes it interesting is the same chemistry that makes it allergenic — those are not two separate facts.

Table of Contents

  1. Overview
  2. Names and Identification
  3. The Honest Evidence Picture: No Human Trials
  4. Traditional Use Across Southeast Asia
  5. Active Compounds: The Sesquiterpene Lactones
  6. Deoxyelephantopin and the Cancer Literature
  7. Fever, Inflammation and the NF-κB Story
  8. Liver Claims
  9. Wounds and Skin Use
  10. Why This Plant Is a Contact Allergen
  11. Forms and Preparations
  12. Dosage
  13. Cautions and Contraindications
  14. Key Research Papers
  15. Connections

Overview

Elephantopus scaber is a perennial herb of the daisy family (Asteraceae), tribe Vernonieae — the same tribe as the ironweeds and as Vernonia amygdalina, the African bitter leaf. Its growth form is distinctive and is the reason for its name: a flat basal rosette of large, rough, oblong leaves pressed down against the ground, from which a wiry, sparsely leafed flowering stalk rises 30–60 cm. The genus name is from Greek elephas (elephant) and pous (foot); the species epithet scaber means "rough," and the leaves genuinely are — sandpapery to the touch, which is a reliable field character.

The flowers are small and easy to miss: pale purple to lavender florets gathered into heads that are themselves clustered into a compound head, each subtended by a set of leafy bracts. The plant flowers over a long season and self-seeds readily.

It grows in open, disturbed, sunny ground — roadsides, grazed grassland, plantation edges, waste plots, riverside banks — and is common enough throughout tropical Asia to be treated as a weed. Its range extends across India, Sri Lanka, Bangladesh, Myanmar, Thailand, Vietnam, Cambodia, Laos, southern China, Taiwan, Malaysia, Indonesia and the Philippines, and it has spread as a pantropical weed into Africa and the Americas.

The whole plant is used, roots included, most often as a decoction of the dried aerial parts and root. In several traditions the fresh leaf is pounded and applied directly to boils and wounds. It is intensely bitter — the Chinese name means "earth gall," gall being the reference point for bitterness — which is why it is a medicine and not a vegetable.

Names and Identification

Binomial: Elephantopus scaber L.
Family: Asteraceae (Compositae), tribe Vernonieae
English: prickly-leaved elephant's foot, elephant's foot, tobacco weed

Regional names

Name confusions — three of them, and they matter

1. "Elephant's foot" is several completely different plants. The English name is shared with Dioscorea elephantipes, a South African caudiciform vine grown as an ornamental succulent, and with Amorphophallus paeoniifolius, the elephant foot yam — a large aroid corm eaten as a staple vegetable across India and Southeast Asia. Neither has anything to do with this plant. Searching the English name will bring back all three.

2. Sibling species are used interchangeably. Elephantopus mollis (soft elephant's foot, with white flowers) and Elephantopus tomentosus occupy the same habitats, are used in the same traditions, and are commonly harvested and sold under the same local names. Pseudelephantopus spicatus is a further lookalike from a closely related genus. Their chemistry overlaps but is not identical, and material sold as E. scaber may be any of them. Wild-collected herb from a market is not a controlled identity.

3. The Vietnamese name places it among the chrysanthemums, which is botanically accurate at family level and misleading at species level. Cúc covers many Asteraceae; the plant is not a chrysanthemum in the sense of the tea flower (Chrysanthemum morifolium), and their uses and chemistry differ substantially.

The Honest Evidence Picture: No Human Trials

Stated plainly, since the rest of the page depends on it:

The gap between "kills cancer cells in a dish" and "helps a person with cancer" is enormous and it is where the overwhelming majority of candidate compounds die. Roughly nineteen out of twenty drugs that enter human trials at all — already having survived years of preclinical filtering — never reach approval, and oncology has the worst attrition of any field. A compound that has never entered a human trial is at a far earlier point than that.

Traditional Use Across Southeast Asia

What is notable about elephant's foot is how consistent its traditional indications are across traditions that developed independently. Four themes recur nearly everywhere it grows: fever, liver, swelling/oedema, and topical use on wounds and boils.

Vietnam — thuốc nam

In Vietnamese folk medicine (thuốc nam, "southern medicine," as distinct from imported Chinese practice), cúc chỉ thiên is a cooling and clearing herb. The whole plant is decocted for fevers, for jaundice and liver complaints, for oedema, and for sore throat and coughs. The fresh plant is pounded into a poultice for boils, abscesses and infected wounds.

Indonesia and Malaysia — jamu

As tapak liman, the plant is a recognised jamu ingredient, used for fevers, as a general tonic and "cleanser," for wounds, and in postpartum recovery formulations. It is sold in Indonesian markets as dried whole plant and appears in packaged jamu preparations.

Southern China

Under the name di dan cao, it belongs to the class of herbs that "clear heat and resolve toxicity" — the traditional category covering acute infections and inflammatory conditions. Its recorded indications include sore throat, tonsillitis, fever, acute hepatitis, oedema, dysentery, and topical use on snakebite and boils. It is a folk and regional herb rather than one of the central Chinese materia medica items.

Thailand

Under the evocative name do mai ru lom, the root in particular is marketed as a male tonic and general strengthener, and this is now its most visible commercial use in Thailand. Note that this indication is the one with the least mechanistic or experimental support of any on this page.

India and the Philippines

In Indian folk practice the leaf paste is applied to eczema, ulcers and wounds, and decoctions are used for fever and dysuria. In the Philippines the plant appears in traditional practice for similar febrile and topical indications.

The consistency across these traditions is worth something as a signal that the plant does something — it is at least the kind of plant that gets noticed. It is not evidence of efficacy for any specific condition.

Active Compounds: The Sesquiterpene Lactones

The pharmacologically interesting fraction of this plant is a family of germacranolide sesquiterpene lactones. The named ones are:

Alongside these the plant contains ordinary and less remarkable constituents: lupeol, epifriedelinol and stigmasterol (triterpenes and sterols), luteolin-7-glucoside and other flavonoid glycosides, and caffeoylquinic acids of the chlorogenic acid family. These contribute general antioxidant activity and are found in hundreds of other plants.

The one chemical fact that explains everything else on this page

Sesquiterpene lactones of this type carry an α-methylene-γ-butyrolactone group. In plain terms, that is a strained, electron-poor double bond sitting next to a carbonyl, and it behaves as a Michael acceptor — it reacts irreversibly with soft nucleophiles. The most abundant soft nucleophile in any cell is the thiol group of cysteine, present in glutathione and in the active or regulatory sites of a great many proteins.

So these molecules covalently modify cysteine residues. That single property accounts for:

One mechanism, four consequences. Any page that presents the anticancer activity without the allergy and glutathione consequences has understood only a quarter of the chemistry.

Deoxyelephantopin and the Cancer Literature

This is the largest body of research on the plant and the one most in need of careful framing.

What has actually been shown

In cell culture: deoxyelephantopin and isodeoxyelephantopin inhibit growth and induce apoptosis in a broad range of human cancer cell lines — nasopharyngeal carcinoma, breast (including the triple-negative MDA-MB-231 line), cervical, hepatocellular, lung, colorectal and leukaemia lines — at low micromolar concentrations. Reported mechanisms include NF-κB inhibition, generation of reactive oxygen species, mitochondrial apoptosis with cytochrome c release and caspase activation, endoplasmic reticulum stress, cell-cycle arrest, autophagy modulation, and Nrf2 pathway activation. Some studies report sensitisation of resistant lines to conventional chemotherapy agents.

In mice: deoxyelephantopin has reduced tumour growth in mouse models, including the TS/A mammary carcinoma allograft in BALB/c mice, with reported effects on tumour volume and on metastasis. Reports generally describe the compound as tolerated at the doses used.

This is a coherent, multi-laboratory preclinical package. It is a reasonable basis for a medicinal-chemistry programme.

What has not been shown, and why the gap is not a formality

Please read this if you or someone you love has cancer

This is where the honest version of this page matters most. Do not substitute this plant, or any preparation of it, for cancer treatment. The reasons are concrete rather than defensive:

If you are in treatment and want to take a herbal product, tell your oncology team. They cannot advise on what they do not know about.

Fever, Inflammation and the NF-κB Story

The traditional fever and inflammation indications have the most coherent mechanistic story on this page, and it is the same one as above: NF-κB is the master transcription factor for inflammatory gene expression, and sesquiterpene lactones inhibit it covalently. Blocking NF-κB reduces the transcription of TNF-α, interleukin-1β, interleukin-6, COX-2 and inducible nitric oxide synthase — which is, in effect, the entire acute inflammatory programme.

The evidence level: cell culture (usually LPS-stimulated macrophage lines, where extracts and isolated lactones reduce nitric oxide and cytokine output) and rodent models (carrageenan paw oedema, and yeast- or LPS-induced fever). No human data.

It is worth noticing that this same mechanism is shared by feverfew's parthenolide, and that feverfew — which does have human migraine trial data, of mixed quality — is a useful reference point for how modest the clinical translation of a potent in vitro NF-κB inhibitor can turn out to be.

The practical point about fever specifically: fever in an adult that is high, persistent beyond a few days, or accompanied by confusion, stiff neck, breathlessness, rash or severe pain needs medical assessment. In the regions where this plant grows, the differential includes dengue, malaria, typhoid, leptospirosis and melioidosis — several of which are treatable and several of which are lethal if missed.

Liver Claims

Traditional use for jaundice and hepatitis is consistent across Vietnamese, Chinese and Indonesian practice, and rodent hepatoprotection studies exist — the standard carbon tetrachloride and paracetamol models, with reduced transaminase elevation and reduced histological damage. Lupeol and the flavonoid fraction, rather than the sesquiterpene lactones, are the usual proposed contributors.

No human data exists. And here there is a specific reason for caution that runs opposite to the traditional claim: the liver is where glutathione conjugation happens, and Michael-acceptor compounds consume glutathione. Concentrated extracts of a sesquiterpene-lactone-rich plant are therefore a theoretical hepatic burden, not obviously a hepatic benefit, and this has not been studied at all in humans.

Anyone with existing liver disease, or taking a drug with known hepatotoxicity, has the strongest reason to avoid concentrated preparations — which is the reverse of what the traditional indication would suggest.

Wounds and Skin Use

Pounded fresh leaf applied to boils, abscesses and infected wounds is one of the most widespread uses of this plant, and there is a coherent rationale: sesquiterpene lactones have documented antibacterial activity in vitro, and reducing local inflammation is plausibly useful on an inflamed lesion. Rodent wound-healing models have reported faster closure with plant extract.

Two counterweights, both important:

Why This Plant Is a Contact Allergen

This deserves its own section because it is the best-established human-relevant fact about the chemistry of this plant — the one thing in this entire page with a solid clinical literature behind it.

Sesquiterpene lactone contact allergy is a recognised, well-characterised dermatological entity. "Sesquiterpene lactone mix" is a standard screening allergen in patch-test series worldwide, and Compositae dermatitis is a familiar diagnosis in occupational and general dermatology. The mechanism is exactly the reactivity described earlier: the α-methylene-γ-butyrolactone binds skin proteins covalently, creating a hapten-protein complex the immune system learns to recognise.

Three features make this clinically significant:

Practical advice: if you have known ragweed, chrysanthemum, feverfew, chamomile, arnica or marigold sensitivity, avoid topical preparations of this plant. If you use it topically at all, patch-test a small area for 48 hours first, and stop at the first sign of itching, redness or small blisters — which typically appear one to three days after exposure rather than immediately.

Forms and Preparations

What to look for on a label

Dosage

No established or evidence-based dose exists. There has been no human dose-finding study, no pharmacokinetic study, and no human toxicology study. Anyone quoting a precise therapeutic dose in milligrams of deoxyelephantopin is extrapolating from mouse experiments, which is not a valid way to set a human dose.

Traditional practice, for description only: decoctions are typically made from roughly 10–30 g of dried whole plant per day, simmered and divided into two or three portions, and generally taken short-term for an acute complaint rather than continuously.

Two observations about that traditional pattern that are worth taking seriously. First, it is short-term acute use — days, for a fever or a boil — not the daily long-term supplementation that capsule products imply. Second, a dilute water decoction of whole plant delivers a far smaller and far more diluted dose of sesquiterpene lactones than a concentrated ethanolic extract in a capsule. The traditional safety record, such as it is, belongs to the traditional preparation and does not transfer to the modern one.

Cautions and Contraindications

Do not use it to treat cancer

Restating the central warning. The entire deoxyelephantopin oncology literature is in vitro and rodent. There is no human trial. Substituting an untested plant for cancer treatment is associated with materially worse survival, and there is a plausible, unstudied risk of interference with chemotherapy and radiotherapy through the plant's effects on glutathione, reactive oxygen species and the Nrf2 pathway. If you are in treatment, tell your oncology team about anything you take.

Asteraceae allergy and cross-reactivity

Anyone sensitised to ragweed, chrysanthemum, feverfew, chamomile, arnica, calendula, artichoke, lettuce or dandelion should assume cross-reactivity and avoid this plant, particularly topically. Sesquiterpene lactone sensitisation is permanent. Patch-test before any repeated skin use.

Pregnancy and breastfeeding

Avoid entirely. Sesquiterpene lactones are cytotoxic to dividing cells, several plants in this class have traditional emmenagogue and abortifacient reputations, and there is no reproductive toxicology data. Do not use this plant while pregnant, attempting to conceive, or breastfeeding.

Liver disease and hepatotoxic drugs

Concentrated extracts consume glutathione, which is the liver's principal detoxification reserve. Avoid if you have liver disease, drink heavily, or take drugs with known hepatotoxicity — and note that this is the opposite of what the traditional liver indication would suggest.

Children

Avoid. There is no paediatric safety data, children have proportionally less glutathione reserve, and febrile illness in a child needs a diagnosis.

Surgery and immunosuppressants

Stop at least two weeks before planned surgery. Because the plant's constituents modulate NF-κB and inflammatory signalling, treat combination with immunosuppressant drugs as an unstudied interaction.

Species identity and provenance

Wild-collected material may be E. mollis, E. tomentosus or a Pseudelephantopus. It is also usually collected from roadsides and disturbed ground, which carries the usual risks: vehicle-related metal deposition, herbicide residue, and contamination from animals.

Fever is a symptom, not a diagnosis

In the regions where this plant is used, a fever may be dengue, malaria, typhoid, leptospirosis, melioidosis or tuberculosis. Several are lethal untreated and several are readily treatable. A bitter decoction that suppresses the fever without touching the cause is a dangerous thing to rely on.

Key Research Papers

A note on the links. Every link goes to a PubMed search rather than a numeric identifier. A mistyped PMID silently sends you to a different paper; a search always resolves and lets you confirm the record yourself. Author names, titles and journals are plain text so you can verify them independently.

  1. Deoxyelephantopin from Elephantopus scaber — antitumour activity and mechanism. Find on PubMed. The core of the oncology literature. Read the methods sections: note that they are cell lines and mice.
  2. Isodeoxyelephantopin and NF-κB signalling. Find on PubMed. The mechanistic basis of both the anticancer and the anti-inflammatory claims.
  3. Deoxyelephantopin in mouse mammary carcinoma (TS/A) models. Find on PubMed. The in vivo rodent work.
  4. Sesquiterpene lactones: chemistry and mechanism of NF-κB inhibition by cysteine alkylation. Find on PubMed. Explains the single chemical property underlying everything on this page.
  5. Sesquiterpene lactone contact allergy and Compositae dermatitis. Find on PubMed. The best-supported human-relevant fact about this plant class.
  6. Parthenium dermatitis in India — airborne Compositae contact dermatitis. Find on PubMed. The scale of the sesquiterpene lactone allergy problem in South Asia.
  7. Johnson SB, Park HS, Gross CP, Yu JB. Use of alternative medicine for cancer and its impact on survival. Journal of the National Cancer Institute. 2018 — find on PubMed. Also see the companion paper by the same group on refusal of conventional treatment among complementary-medicine users.
  8. Phytochemistry and ethnopharmacology of Elephantopus scaber — reviews. Find on PubMed. Useful for the constituent list; note that these reviews generally do not flag the absence of human data.

Live PubMed Searches

  1. Elephantopus scaber
  2. Deoxyelephantopin
  3. Isodeoxyelephantopin
  4. Scabertopin
  5. Elephantopus scaber clinical trial — check this yourself; it is the emptiest search on the page
  6. Elephantopus scaber hepatoprotective
  7. Sesquiterpene lactone contact dermatitis
  8. Nrf2 and chemoresistance — background to the chemotherapy interaction concern
  9. Tapak liman and jamu
  10. Alternative medicine, treatment refusal and cancer survival

Connections


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