Fleabane

Other Names

Annual fleabaneArgentine fleabaneAster annuusAsthma weedAvoadinhaBakkestjerneBitter boreal daisyBitter daisyBitter fleabaneBitter weedBlood-stanchBlue fleabaneBony-tip fleabaneButterweedCanada fleabaneCanadian fleabaneCanadian horseweedCespica acreCola de CaballoCola de ZorraColt's tailColtstailCommon eastern fleabaneCommon fleabaneCommon horseweedConyzaConyza bonariensisConyza canadensisConyza sumatrensisCow's tailDaisy fleabaneDiplopappus annuusEastern daisy fleabaneErigeronErigeron acrisErigeron annuusErigeron bonariensisErigeron canadensisErigeron crispusErigeron du CanadaErigeron karvinskianusErigeron linifoliusErigeron philadelphicusErigeron strigosusEscoba duraFieldweedFireweedFlax-leaf fleabaneFlax-leaved fleabaneFlax-leaved horseweedFlaxleaf fleabaneFlea wortFleabane daisyFrost-rootFrostweedHairy fleabaneHairy horseweedHierba de caballoHierba impiaHogweedHorsetailHorseweedJarillaKarwinsky's fleabaneLatin American fleabaneLeptilon canadenseMarestailMarsh fleabaneMexican fleabaneMourning widowOlivardaPhiladelphia daisyPhiladelphia fleabanePoor robin's plantainPrairie fleabanePrideweedRobin's-plantainRough conyzaRough fleabaneSanta Barbara daisyScharfes BerufkrautSkervishSkevishSpanish daisySpreading daisySpreading fleabaneStenactis annuaSweet scabiousTall fleabaneTrimorpha acrisVergerette acreVergerette du CanadaVergerette rudeWavy-leaf fleabaneWhite-topped fleabane

Synopsis

Fleabane (Erigeron canadensis / Conyza canadensis): A Comprehensive Reference

1. Identity and Botanical Classification

Taxonomy and Nomenclature

Fleabane most commonly refers to Erigeron canadensis (synonym Conyza canadensis), an annual plant native throughout most of North America and Central America that is also widely naturalized in Eurasia and Australia. Common names include horseweed, Canadian horseweed, Canadian fleabane, coltstail, marestail, and butterweed. The plant belongs to the genus Erigeron, a diverse group of flowering plants within the family Asteraceae.

The genus Erigeron is contested in classification, as many countries still use a different scientific name — Conyza — for some species. The general consensus in taxonomic literature is that the Erigeron genus also incorporates the more specific genus Conyza. Erigeron bonariensis L. (also known as Conyza bonariensis (L.) Cronquist) is a closely related member of the Asteraceae family that can grow up to one metre in height and is either an annual or perennial herbaceous plant.

The primary species used medicinally include Erigeron canadensis, also known as horseweed or Canadian fleabane, and Erigeron annuus, commonly called daisy fleabane. A third species of note is Erigeron bonariensis, sometimes called flaxleaf fleabane or hairy fleabane, which has its own distinct phytochemical and pharmacological profile documented in the scientific literature.

Morphology

Erigeron canadensis is an annual herbaceous plant growing to 1.5 metres (5 feet) tall with sparsely hairy stems. The leaves are unstalked and slender, measuring 2–10 centimetres in length and up to 1 cm wide, with a coarsely toothed margin, growing in an alternate spiral up the stem, with the lower ones withering early. The flower heads are produced in dense inflorescences and are approximately 1 cm in diameter. Each individual flower has a ring of white or pale purple ray florets and a centre of yellow disc florets.

Erigeron canadensis can easily be confused with Erigeron sumatrensis, which may grow to a height of 2 m, and the more hairy Erigeron bonariensis, which does not exceed 1 m.

Etymology

The name "fleabane" comes from an old belief that the dried plant repelled fleas. The name is often associated with the plant's historical use in repelling insects, although its primary medicinal significance lies in its pharmacological and chemical properties.

Habitat and Distribution

Erigeron canadensis is native to North America but has become widespread in many other parts of the world. It typically grows in disturbed areas, roadsides, and fields. It is adaptable from waste grounds to cultivated fields, thriving in temperate zones across North America, Europe, and Asia.

Common Preparations and Forms

Identification studies of the active ingredients in this medicinal plant have revealed phytochemicals including essential oil components, saponins, diterpenoids, terpenoids, tannins, anthraquinone, steroids, flavonoids, choline, resins, and waxes. In particular, the flowering parts of E. canadensis used in traditional medicine have been found to contain active substances with diuretic, hemostyptic, tonic, antidiarrheal, antifungal, antimicrobial, anthelmintic, astringent, antioxidant, anti-inflammatory, anticoagulant, anticancer, mutagenic, gastric protective, and skin depigmentation effects.

The plant is used in several forms across traditional and contemporary herbal practice:

Infusion (tea): Aerial parts steeped in hot water, consumed internally for gastrointestinal or respiratory conditions.
Decoction: Boiled preparation of aerial parts or roots, used internally or externally.
Essential oil: The volatile oil of horseweed has been applied against bronchitis and cystitis.
Tincture / liquid extract: Hydroalcoholic preparation of the herb.
Topical poultice: In Chinese folk medicine, horseweed has been applied for the treatment of wounds, swellings, and pain caused by arthritis.
Snuff: In traditional North American herbal medicine, Canada fleabane was taken as a snuff to stimulate sneezing during the course of a cold.
Steam inhalation: Canadian fleabane was boiled to make steam for sweat lodges and burned to create a smoke that warded off insects.

2. Traditional and Historical Use

Indigenous North American Use

Canadian horseweed was used by numerous Native American peoples to treat a variety of ailments. It was used by the Seminole as a cough and cold medicine. The Navajo and Chippewa used Canadian horseweed for stomach pain, and the Iroquois used an infusion of the plant to combat fevers.

The Zuni people inserted the crushed flowers of E. canadensis var. canadensis into the nostrils to cause sneezing, relieving rhinitis. E. canadensis infusion of aerial parts taken and steam inhaled was recommended as a cough, cold, and asthma medicine by the Seminole people.

Seminole ethnobotanical records document the infusion of leaves and bark taken and steam inhaled for runny nose, stuffy head, sore throat, coughs, and asthma.

19th-Century American and Eclectic Medical Traditions

According to Alice Henkel's 1904 USDA Bulletin No. 188, "Weeds Used as Medicine," Canadian fleabane had the common name "blood stanch," which indicated its use for the arresting of hemorrhages from various sources and the bleeding of wounds. She also noted that it was useful for diarrhea and dropsy.

According to Felter and Lloyd's King's American Dispensatory, erigeron was used for watery diarrhea. Oil of erigeron, though not astringent to taste, acts as an astringent and has a styptic influence, making it useful for local application to hemorrhoids and small wound bleeds, though it was considered too acrid to be used alone and should be combined with oil. An infusion could be given hot or cold for the stomach. A snuff of powdered leaves was used for epistaxis, and syrup was considered effective for cough, pneumonia, and blood-tinged bronchial expectoration.

By the mid-19th century, early American physicians cited Conyza canadensis in pharmacopeias for its diuretic and astringent properties.

Chinese and Asian Folk Medicine

The plant Conyza canadensis belongs to the Asteraceae family and was used as traditional medicine in China, Pakistan, India, and Africa for the treatment of various diseases caused by bacteria, fungi, or viruses. Erigeron canadensis, called horseweed, is widely distributed in China and is one of the herbaceous Chinese medicines used to treat intestinal diseases.

In Korean tradition, this plant has been used as a folk medicine to treat allergic diarrhea, stomatitis, otitis media, conjunctivitis, and acute toothache.

European Folk Traditions

The aerial parts and roots of this plant have been used all over the world as traditional or official herbal medicines for the treatment of gastrointestinal symptoms, most commonly diarrhoea and dysentery, and as a diuretic agent. In Central Europe, folk medicine embraced Erigeron canadensis around the 1900s as a mild expectorant.

Traditional Uses Across Cultures — Summary of Indications

The aerial parts of this weed are widely used in folk medicine to treat headache, dental pain, rheumatism, kidney problems, gastrointestinal disorders, and respiratory tract infections, in addition to wounds and skin burns.

Gastrointestinal: Due to its high astringency level and antimicrobial nature, this plant has traditionally been used to treat watery diarrhea and dysentery where microorganisms were purported to be the cause.
Hemorrhage / bleeding: Due to its antihemorrhagic properties, Erigeron has long been used for any condition characterized by excessive bleeding, including heavy menstrual flow and chronic nosebleeds.
Respiratory: In traditional North American herbal medicine, Canada fleabane was boiled to make steam for sweat lodges and taken as a snuff to stimulate sneezing during the course of a cold.
Topical / wound healing: An infusion of the plant has been used to treat internal haemorrhages or applied externally to treat gonorrhoea and bleeding piles.

3. Key Constituents and Active Compounds

General Phytochemical Profile

Erigeron canadensis (syn. Conyza canadensis) contains saponins, diterpenoids, terpenoids, glycosides, tannin, anthraquinone, steroids, and flavonoids. Bioactive compounds isolated from the Conyza genus include alkenynes, terpenoids, terpenes, saponins, flavonoids, sterols, phenylpropanoyl esters, lactones, tannins, and coumarins.

Essential Oil Composition

The composition of the essential oil of Erigeron canadensis growing in west Japan, investigated by capillary GC and GC/MS, was found to contain 47 volatile components of which 91.0% were terpenoid. The main constituents were limonene (31.2%), camphene (14.2%), and germacrene D (11.3%), accounting for 56.7% of the oil. Non-terpenoid acetylenic compounds have also been detected.

In another analysis, essential oil of E. canadensis extracted by hydrodistillation yielded a total of 23 identified components, representing 95.9% of the oil. The main constituents were monoterpenoids including limonene (57.2%), camphene (2.5%), α-pinene (1.9%), and β-pinene (2.1%), along with sesquiterpenoids including caryophyllene (6.7%), germacrene D (4.9%), and α-curcumene (3.0%). A few non-terpenoid acetylenic compounds (4.8%) were also detected.

The major constituent of the oil obtained from the aerial parts of horseweed was limonene (up to 79.2%), while the main component of root oil was 2Z,8Z-matricaria ester. The aerial part oil contains mono- and sesquiterpenes in 8.6% and 6.6%, and acetylenes in 3.4%. The main compound of the root oil (2Z,8Z-matricaria ester) can be detected in the aerial herb only in small quantity, while, conversely, the main component of the herb (limonene) is present in root oil only in about 1%.

A compositional revision of essential oils from fourteen Erigeron species worldwide revealed significant interspecies as well as intraspecies variability. Chemical variability (both quantitative and qualitative) was determined between different plant organs and at various phenological stages. Limonene, δ-3-carene, matricaria ester, lachnophyllum ester, germacrene D, β-caryophyllene, β-farnesene, α-bergamotene, and allo-aromadendrene were among the most prevalent characteristic compounds.

The preparation method, technique, and duration employed in the extraction process are all of paramount importance to the composition of the final product.

Sesquiterpene Hydrocarbons

Eight sesquiterpenic hydrocarbons — β-santalene, β-himachalene, cuparene, α-curcumene, γ-cadinene, and three other unidentified hydrocarbons — were isolated from the above-ground part of the plant. As discussed in the anti-inflammatory section below, some of these compounds demonstrate direct pharmacological activity.

Phenolic Acids and Flavonoids

GC/MS analysis of the hydro-distilled essential oils from the fresh aerial parts (inflorescence heads, leaves, and stems) of Conyza canadensis from Jordan was carried out. The methanolic extract from the whole aerial parts was additionally examined for total phenolic content, total flavonoids content, DPPH radical scavenging activity, iron chelating activity, and was analyzed with LC-MS/MS for certain phenolic compounds and flavonoids.

GC/MS analysis of the essential oils obtained from different aerial parts revealed the presence of (2E, 8Z)-matricaria ester as the main component, amounting to 15.4% in inflorescences, 60.7% in leaves, and 31.6% in stems of the total content. Oxygenated monoterpenes were the main class of volatile compounds detected in the inflorescence essential oil.

Additional Isolated Compounds

Conyzapyranone B showed considerable antiproliferative effects against cancer cell lines in laboratory studies. The plant also contains novel sphingolipids, and two species-specific flavonoids — conyzolide and conyzoflavone — have been isolated and studied for antimicrobial activity.

4. Mechanisms of Action

Astringency and Hemostasis

Fleabane contains tannins, flavonoids, and volatile oils that give it astringent, anti-inflammatory, and mildly antimicrobial properties. Tannins exert their effects by binding and precipitating proteins in tissue, which reduces inflammation, bleeding, and excess secretions, explaining the traditional use for diarrhea, hemorrhoids, and mucosal irritation.

Anti-Inflammatory Pathways

The methanol extract of E. canadensis (ECM) inhibited LPS-induced nuclear translocations and transactivities of NF-κB in macrophage cell studies. Phosphorylation of mitogen-activated protein kinases (MAPKs) — including ERK1/2, p38, and JNK — was significantly suppressed by ECM in LPS-stimulated RAW264.7 macrophages. ECM also induced heme oxygenase-1 (HO-1) protein expression in a dose-dependent manner. When HO-1 was selectively inhibited by zinc protoporphyrin (ZnPP), the ECM-induced suppression of nitric oxide production was abolished, suggesting that ECM-induced HO-1 expression was partly responsible for the anti-inflammatory effects.

Petroleum ether and ethanolic extracts from the above-ground part of Conyza canadensis exhibit a significant anti-inflammatory effect on rats with carrageenan and formalin oedema. Eight sesquiterpenic hydrocarbons with the highest anti-inflammatory activity were found in the petroleum ether fraction: β-santalene, β-himachalene, cuparene, α-curcumene, γ-cadinene, and three unidentified hydrocarbons. Of these, β-himachalene was further studied and its anti-inflammatory activity was demonstrated.

Anticoagulant and Antiplatelet Mechanisms

A polyphenolic-polysaccharide preparation from Erigeron canadensis demonstrated in vivo anticoagulant activity, with the effect neutralized by protamine sulfate. It also had anti-platelet activity limited to the cyclooxygenase pathway, induced by arachidonic acid. The fraction of the highest anticoagulant activity measured 7–9 IU/mg of heparin standard, expressed in aPTT.

Both the whole plant preparation and its most active fraction inhibited thrombin and factor Xa amidolytic activities in the presence of antithrombin, though much higher concentrations were required to obtain the same effects as standard anticoagulants.

Melanogenesis Inhibition

Erigeron canadensis extract was investigated for its effects on melanogenesis in cultured B16F10 mouse melanoma cells. The extract down-regulated melanin synthesis effectively at a non-toxic concentration. One active fraction showed melanin inhibition of 48.0% at 100 mg/ml, 2.5 times more efficient than the depigmenting effect of commercial arbutin (17.5%). Investigation of the mechanism revealed that this fraction inhibited melanin synthesis in B16F10 cells by decreasing protein levels of melanogenic enzymes, especially tyrosinase.

Antiviral Mechanisms

Ethyl acetate, chloroform, butanol, and methanol extracts of the aerial parts of Conyza canadensis were investigated for antiviral activity against human cytomegalovirus (HCMV) AD-169 and Cox-B3 viruses by modification of the shell-vial assay. The results showed that butanol and methanol extracts had the most potent antiviral activity against both viruses. The plant's extracts achieved up to 100% antiviral activity against human cytomegalovirus at specific concentrations. These results are from in vitro studies and have not yet been replicated in human clinical trials.

5. Scientific Evidence by Area of Use

5.1 Antimicrobial Activity

The antimicrobial properties of the essential oils of various Erigeron species have been among the most extensively investigated areas. Antifungal and antibacterial effects against various strains have been demonstrated by the oils of E. acris, E. annuus, E. bonariensis, E. canadensis, E. floribundus, E. incanus, E. mucronatus, E. speciosus, and E. ramosus.

The antimicrobial activities of the essential oils of Conyza canadensis were tested on Gram-positive bacteria (Enterococcus faecalis, Staphylococcus aureus, and Streptococcus pyogenes), Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), reference fungal strains, and fungal strains isolated from patients (Candida, Cryptococcus, Trichophyton, Rhodotorula, and Aspergillus) by agar disc diffusion and broth dilution methods.

For E. floribundus, the essential oil showed activity against Staphylococcus aureus (inhibition zone diameter of 14 mm, minimum inhibitory concentration of 512 µg/mL). It inhibited the NadD enzyme from S. aureus (IC50 of 98 µg/mL), with no effects on mammalian orthologue enzymes. Trypanosoma brucei proliferation was inhibited with IC50 values of 33.5 µg/mL with the essential oil and 5.6 µg/mL with the active component limonene.

Evidence strength: Evidence for antimicrobial activity is based entirely on in vitro laboratory testing. No controlled human trials have been conducted. These findings demonstrate potential but cannot be directly extrapolated to clinical efficacy.

5.2 Anti-Inflammatory Activity

Modern pharmacological study showed that E. canadensis has strong bioactivities including anti-inflammation, anticoagulant and antiplatelet activity, inhibition of melanogenesis, cytotoxicity, and antifungal activity.

In one study, methanol extracts were evaluated for antioxidant activity by DPPH•, ABTS•+, and FRAP assays. The cytotoxic effects of the extracts were investigated on DU145 prostate cancer and A549 lung cancer cell lines. The anti-inflammatory effects of extracts were investigated by measuring NO amount, TNF-α, IFN-γ, and PGE2 levels in lipopolysaccharide-stimulated RAW 264.7 cells.

Evidence strength: Anti-inflammatory effects have been demonstrated in rodent models and cell culture studies. The NF-κB and MAPK suppression findings represent a meaningful mechanistic advance, but all studies identified are preclinical. No human clinical trials have been published on the anti-inflammatory application of fleabane.

5.3 Gastric Protection

Although the plant has been used as a folk medicine to treat allergic diarrhea, stomatitis, otitis media, conjunctivitis, and acute toothache, and its anti-inflammatory and anticoagulant activities have been reported, the effect on gastric ulcer had been understudied until more recently. In a mouse study, the 70% ethanolic extract (EEC) of the aerial parts of E. canadensis was found to protect the gastric mucosa against ulcers induced by HCl/ethanol. Administration of HCl/ethanol produced lesions on the gastric mucosa which were significantly and dose-dependently reduced from 74.4% ulceration percentage to 14.4% in the animals pretreated with the extract.

In the group pretreated with extract at the dose of 100 mg/kg, the protective effect was higher than that of sucralfate used as a reference drug.

Evidence strength: Animal study (mouse model) only. No human clinical data are available for the gastroprotective application.

5.4 Anticoagulant and Cardiovascular Effects

Several reports on Erigeron spp. have also documented inhibition of platelet aggregation, improvement in microcirculation, dilation of blood vessels, and increase in cerebral blood flow.

The polyphenolic-polysaccharide preparation from E. canadensis studied by Pawlaczyk et al. (2011) demonstrated anticoagulant activity in vivo (animal studies) and antiplatelet activity in vitro through the cyclooxygenase pathway. This work, published in Thrombosis Research, represents the most rigorous preclinical investigation of fleabane's coagulation effects; no human trials are available.

5.5 Antioxidant Activity

In one study of E. floribundus essential oil, remarkable ferric reducing antioxidant power was measured (tocopherol-equivalent antioxidant capacity, TEAC = 411.9 μmol·TE/g).

Methanolic extracts of C. canadensis have been assessed for Total Phenolic Content (TPC), Total Flavonoid Content (TFC), and antioxidant activity by DPPH, ABTS, and FRAP assays in multiple independent studies.

Evidence strength: Antioxidant activity is consistently demonstrated in cell-free assays and cell culture models. Clinical translation remains undemonstrated.

5.6 Antitussive (Cough-Suppressing) Activity

A polyphenolic polysaccharide-protein complex was isolated from Erigeron flowers and investigated for antitussive properties. This complex has been characterized by chromatographic and spectroscopic methods. Evidence for antitussive effects in humans is not yet established from clinical trials; the primary evidence is traditional use across multiple cultures and preliminary laboratory investigation.

5.7 Skin Depigmentation

A fraction of E. canadensis extract showed melanin inhibition of 48.0% at 100 mg/ml in B16F10 melanoma cell culture, approximately 2.5 times more efficient than the depigmenting effect of commercial arbutin (17.5%). The active fraction inhibited melanin synthesis by decreasing protein levels of melanogenic enzymes, especially tyrosinase, as well as TRP-1 and TRP-2.

Evidence strength: In vitro study only, using a mouse melanoma cell line. No human clinical or dermatological trial data are available.

5.8 Nematocidal (Antiparasitic) Activity

A study of nematocidal effects of various plants showed that fleabane shoots caused greater than 98% fatality of the nematode larvae of Strongyloides papillosus, the intestinal threadworm.

C. canadensis, along with closely related species, has exhibited antidiarrhoeal, antimicrobial, antiparasitic, antinociceptive, antioxidant, and expectorant activities, as well as antiaggregatory effects on blood platelets and inhibition of catecholamine secretion.

Evidence strength: In vitro/laboratory testing only; not studied in human clinical settings.

Overall Evidence Summary

Unlike more popular herbs such as echinacea, Erigeron has very little research to back up the more anecdotal uses. The body of evidence for fleabane is almost exclusively preclinical: in vitro (cell culture), animal models, and ethnobotanical records. No large-scale randomized controlled trials in humans have been conducted for any indication. All pharmacological findings described in peer-reviewed literature should be understood as preliminary observations requiring confirmation in rigorous human studies.

6. Body Systems and Health Areas Associated with Fleabane

Gastrointestinal system: Diarrhea, dysentery, hemorrhage, gastric ulcer (murine model only), stomatitis, digestive toning via tannin astringency.
Respiratory system: Cough, cold, asthma (steam inhalation), bronchitis (volatile oil use), expectorant effects.
Cardiovascular/hematological system: Platelet aggregation inhibition, anticoagulant effects, potential hemorrhage arrest; these effects reflect opposing traditional uses (both styptic and anticoagulant depending on the preparation).
Integumentary (skin) system: Topical use for wounds and burns, contact dermatitis risk from plant contact, potential skin depigmentation via tyrosinase inhibition (in vitro only).
Urinary system: Diuretic use documented across multiple traditional medicine systems.
Musculoskeletal system: Traditional use for rheumatism and arthritis (topical in Chinese medicine).
Immune/anti-infective: Antimicrobial, antifungal, antiviral, and antiparasitic activities demonstrated in laboratory models.

7. Dosage Forms and Doses Reported in Studies

There is no established standardized clinical dosage for fleabane, as no formal human clinical trials have defined optimal doses. The following figures are drawn directly from the available scientific and traditional literature:

Animal gastric ulcer study: In the murine gastric ulcer suppression study, the dose of 100 mg/kg of ethanolic extract exerted a protective effect higher than that of sucralfate used as a reference drug.
Anticoagulant study: The fraction of highest anticoagulant activity was reported as 7–9 IU/mg of heparin standard, expressed in aPTT.
Skin depigmentation study: The active fraction demonstrated melanin inhibition of 48.0% at a concentration of 100 mg/ml in cell culture.
Traditional tincture dose (herbalist practice, not from clinical trial): Tincture use at 1–2 ml three times per day has been cited in contemporary Western herbal practice; these figures are not derived from clinical studies.

No pharmacokinetic data (absorption, distribution, metabolism, excretion) have been published in peer-reviewed form for any fleabane preparation in humans.

8. Safety Considerations and Drug Interactions

Contact Dermatitis and Asteraceae Allergy

Skin contact with Erigeron canadensis can cause contact dermatitis in some individuals. People with sensitivity to plants in the Asteraceae family should be cautious.

In particular, sesquiterpene lactones (SLs) present in Asteraceae plants may cause sensitization resulting in skin irritation and inflammation. Asteraceae-related allergy symptoms can involve eczema, hay fever, asthma, or even anaphylaxis.

Contact with Erigeron bonariensis can cause dermatitis, especially in sensitive individuals, with this reaction attributed to sesquiterpene lactones present in the plant.

Almost 50% of sesquiterpene lactones are potential contact allergens. These metabolites are present in both fresh and dried plants in various proportions from 0.01 to 8% per dry weight.

Cross-Reactivity in the Asteraceae Family

Horseweed should not be used in individuals who are allergic to Asteraceae family plants such as ragweed, chrysanthemum, marigold, and daisies.

Anticoagulant Interactions

Horseweed may slow the blood clotting process and increase the risk of bleeding and bruising. Concurrent use with blood-thinning medications such as warfarin should be avoided. This caution is grounded in demonstrated in vitro and in vivo anticoagulant and antiplatelet activity of fleabane polyphenolic-polysaccharide preparations.

Pregnancy

Canadian fleabane has been used traditionally for menstrual disorders, and it is advised not to consume this plant if pregnant.

Phytoremediation and Contaminant Risk

Fleabane is a possible phytoremediator for metal-contaminated soils, so individuals who harvest it themselves should take care not to collect it where metal contamination may have occurred.

Glyphosate Resistance

Erigeron canadensis was the first weed to have developed glyphosate resistance, reported in 2001 from Delaware. This fact is of relevance for wild-harvested material, as plants from agricultural areas may have been exposed to herbicides or carry resistance-related genetic changes of unknown safety significance for consumption.

Mutagenicity

Pharmacological studies have shown that Erigeron canadensis exerted mutagenic activity in laboratory assays, in addition to its documented gastric protective effects. The mutagenic potential, identified in cell-based mutagenicity testing, has not been characterized in human safety studies and represents a flagged concern requiring further research before clinical use can be recommended.

References

Health Conditions

Health conditions that Fleabane may help support.

No conditions available.

Body Systems

Body systems that Fleabane may help support.

No body systems available.