Coltsfoot

What is Coltsfoot?

Coltsfoot (Tussilago farfara) is a low, spreading perennial in the daisy family, native to Europe and Asia and naturalised in North America. Its bright yellow flowers appear in early spring before the broad, hoof-shaped leaves, which gave the plant its name. It has a long history as a remedy for coughs and lung complaints.

Traditional & Modern Uses

The botanical name Tussilago means “cough dispeller,” reflecting the plant’s ancient reputation. The leaves and flowers were used as a soothing, mucilage-rich expectorant tea or syrup for coughs, bronchitis, asthma and sore throats, and dried coltsfoot was historically smoked as a “herbal tobacco” to ease the chest. It remains a component of some herbal smoking blends and traditional cough preparations. Modern practice has shifted decisively away from that internal use: because the plant carries hepatotoxic pyrrolizidine alkaloids, the herb is now widely discouraged for ingestion, and the tension between its long traditional record and its documented liver toxicity is the defining fact of the monograph.

Phytochemistry

Coltsfoot’s soothing, demulcent action comes from abundant mucilage (polysaccharides), supported by tannins and the flavonoids rutin, isoquercitrin, quercetin and kaempferol; the sesquiterpene tussilagone is credited in preclinical work with the plant’s expectorant and anti-inflammatory activity ^{1,9,10Reference 1Chen et al. · 2021ReviewA review of the ethnobotanical value, phytochemistry, pharmacology, toxicity and quality control of Tussilago farfara L. (coltsfoot) — reviewView study →Reference 9Choi et al. · 2018In vitroTussilagone suppressed the production and gene expression of MUC5AC mucin — in vitro airway modelView study →Reference 10Hwangbo et al. · 2009In vitroThe anti-inflammatory effect of tussilagone, from Tussilago farfara, is mediated by the induction of heme oxygenase-1 in murine macrophages — in vitroView study →}, and the caffeoylquinic acids — chiefly chlorogenic acid and its dicaffeoyl relatives — carry much of the antitussive/expectorant signal ^{5,6Reference 5Wu et al. · 2016AnimalAntitussive, expectorant, and anti-inflammatory activities of four caffeoylquinic acids isolated from Tussilago farfara — mouse in vivoView study →Reference 6Discovering the major antitussive et al. · 2020In vitrohttps://pubmed.ncbi.nlm.nih.gov/32023945/View study →}. Crucially, coltsfoot also contains hepatotoxic pyrrolizidine alkaloids — chiefly senkirkine, senecionine and tussilagine — which are the compounds that drive its safety restrictions ^{1,2Reference 1Chen et al. · 2021ReviewA review of the ethnobotanical value, phytochemistry, pharmacology, toxicity and quality control of Tussilago farfara L. (coltsfoot) — reviewView study →Reference 2Adamczak et al. · 2013Content of pyrrolizidine alkaloids in the leaves of coltsfoot (Tussilago farfara L.) in Poland — analyticalView study →}. It helps to hold the chemistry in two halves: the beneficial classes (sesquiterpenoids, caffeoylquinic acids, flavonoids and mucilage) sit alongside a harmful one (the pyrrolizidine alkaloids), and the benefit-risk problem is the coexistence of the two in the same leaf.

Constituent Summary

Figures are percent of dried herb where known; the pyrrolizidine-alkaloid content is very low and highly variable (often reported below 0.015%, i.e. micrograms per leaf) and depends strongly on plant part, chemotype and region — so a low average does not guarantee a low dose in any given sample. Sesquiterpenes and flavonoids are documented qualitatively and listed as No Data ^{1,2,45Reference 1Chen et al. · 2021ReviewA review of the ethnobotanical value, phytochemistry, pharmacology, toxicity and quality control of Tussilago farfara L. (coltsfoot) — reviewView study →Reference 2Adamczak et al. · 2013Content of pyrrolizidine alkaloids in the leaves of coltsfoot (Tussilago farfara L.) in Poland — analyticalView study →Reference 45Sensitive determination of pyrrolizidine et al. · 2016Journal of Separation Science. https://pubmed.ncbi.nlm.nih.gov/27673325/View study →}.

Pharmacology & Research

Coltsfoot has a large phytochemical literature (roughly 175 characterised compounds) but a pharmacology base that is almost entirely preclinical — cell-line assays and rodent models, with no registered clinical trials evaluating the whole herb for any indication ^{1,3,4Reference 1Chen et al. · 2021ReviewA review of the ethnobotanical value, phytochemistry, pharmacology, toxicity and quality control of Tussilago farfara L. (coltsfoot) — reviewView study →Reference 3Liu et al. · 2020ReviewFarfarae Flos: a review of botany, traditional uses, phytochemistry, pharmacology, and toxicology — reviewView study →Reference 4Coltsfoot (Tussilago farfara): a review · 2025ReviewNatural Product Research. https://pubmed.ncbi.nlm.nih.gov/40892112/View study →}. The most consistent and heavily replicated signal is anti-inflammatory, driven largely by the sesquiterpenoid tussilagone and a family of caffeoylquinic acids, converging on NF-κB suppression and Nrf2/HO-1 induction ^{10,11,23Reference 10Hwangbo et al. · 2009In vitroThe anti-inflammatory effect of tussilagone, from Tussilago farfara, is mediated by the induction of heme oxygenase-1 in murine macrophages — in vitroView study →Reference 11Cheon et al. · 2018AnimalTussilagone ameliorates inflammatory responses in dextran-sulphate-sodium-induced murine colitis — mouse in vivoView study →Reference 23Lee et al. · 2017In vitroTussilagonone-induced Nrf2 pathway activation protects HepG2 cells from oxidative injury — in vitroView study →}. The traditional respiratory use — cough, phlegm, bronchitis — is supported by animal antitussive/expectorant models and by mucin-suppression and lung-inflammation work, though again only in animals ^{5,9,17Reference 5Wu et al. · 2016AnimalAntitussive, expectorant, and anti-inflammatory activities of four caffeoylquinic acids isolated from Tussilago farfara — mouse in vivoView study →Reference 9Choi et al. · 2018In vitroTussilagone suppressed the production and gene expression of MUC5AC mucin — in vitro airway modelView study →Reference 17Li et al. · 2022In vitroThe ethanol extract of flower buds of Tussilago farfara L. attenuates cigarette-smoke-induced lung inflammation through NLRP3 inflammasome, Nrf2, and NF-κB — mouse in vivo / in vitroView study →}. The single most important caveat is not efficacy but safety: coltsfoot contains hepatotoxic, pro-carcinogenic pyrrolizidine alkaloids (senkirkine, senecionine), and one of the few in vivo whole-herb feeding studies produced liver tumours in rats ^{43Reference 43Hirono et al. · 1976AnimalCarcinogenic activity of coltsfoot, Tussilago farfara L. — rat in vivoView study →}. Effect sizes also depend heavily on preparation — most active-compound work uses isolated tussilagone or solvent fractions given by injection, not the leaf tea the herb is traditionally taken as.

0. Evidence by indication

Support is an experimental score I’m building — a composite weighted by study type (human > animal > in vitro > review) and study volume. It’s a beta: a fast way to rank strength of evidence at a glance, not a validated metric, and I’ll keep honing the formula over time. Each indication name links down to its write-up.

Indication	Support	Rests on
Anti-inflammatory	███████░░░ 68%	Many independent animal/in-vitro studies; NF-κB↓, HO-1↑; no human data.
Antitussive & expectorant	██████░░░░ 62%	Rodent cough/expectorant + mucin models; good prep match to traditional tea; animal only.
Respiratory / lung-protective	██████░░░░ 60%	Strong CS-COPD, PM2.5 and sepsis lung-injury models; mostly isolated tussilagone, often injected.
Antioxidant (Nrf2 cytoprotection)	██████░░░░ 56%	Consistent Nrf2/HO-1 induction in hepatocyte and neuronal cells; in vitro–led.
Neuroprotective	█████░░░░░ 52%	Microglia, PC12 and rat stroke/Parkinson models; no human data.
Anticancer (antiproliferative)	█████░░░░░ 46%	Colon/breast/liver cell lines + a colitis-cancer mouse model; offset by the herb’s own carcinogenicity.
Anti-allergic	████░░░░░░ 44%	One allergic-rhinitis guinea-pig study + mast-cell work; single compound.
Metabolic / anti-diabetic	████░░░░░░ 42%	Aldose-reductase inhibition, one NAFLD mouse model, constituent-level glucose uptake.
Cardiovascular	████░░░░░░ 40%	Antiplatelet in vitro + one atherosclerosis mouse model; two studies.
Antimicrobial	████░░░░░░ 36%	In-vitro screens, largely essential-oil — a preparation the herb isn’t taken as.

1. Anti-inflammatory

This is the deepest and most reproducible part of the literature. The sesquiterpenoid tussilagone induces heme oxygenase-1 (HO-1) in macrophages and suppresses NO, TNF-α and PGE2 production ^{10Reference 10Hwangbo et al. · 2009In vitroThe anti-inflammatory effect of tussilagone, from Tussilago farfara, is mediated by the induction of heme oxygenase-1 in murine macrophages — in vitroView study →}, and reduces colonic inflammation in dextran-sulphate-sodium colitis in mice via NF-κB↓ and Nrf2↑ ^{11Reference 11Cheon et al. · 2018AnimalTussilagone ameliorates inflammatory responses in dextran-sulphate-sodium-induced murine colitis — mouse in vivoView study →}. Multiple isolated sesquiterpenoids independently inhibit LPS-induced NO and cytokine release in BV-2 microglia and RAW264.7 macrophages ^{12,13,16Reference 12Lim et al. · 2015In vitroIn vitro neuroprotective activity of sesquiterpenoids from the flower buds of Tussilago farfara — in vitroView study →Reference 13Sesquiterpenoids from Tussilago farfara et al. · 2014In vitrohttps://pubmed.ncbi.nlm.nih.gov/24963619/View study →Reference 16Sesquiterpenoids from Tussilago farfara: et al. · 2026In vitroChinese Journal of Natural Medicines. https://pubmed.ncbi.nlm.nih.gov/41781124/View study →}, the analogue tussilagonone attenuates psoriasis-like skin inflammation in an imiquimod mouse model ^{14Reference 14Lee et al. · 2020AnimalTussilagonone ameliorates psoriatic features in keratinocytes and imiquimod-induced psoriasis-like skin inflammation — mouse in vivo. https://pubmed.ncbi.nlm.nih.gov/31877316/View study →}, and a whole-plant extract lowered inflammatory markers in rabbits ^{15Reference 15Prunella vulgaris et al. · 2025In vitroJournal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/39442825/View study →}. The convergence of independent groups on the same NF-κB / Nrf2-HO-1 axis is what pushes this above the other indications.

Gap: every study is animal or in vitro, doses and routes vary widely, and no human anti-inflammatory data exist.

2. Antitussive & expectorant

This is the herb’s traditional flagship use, and it is the indication where the tested preparation best matches how coltsfoot is actually taken. In mice, four chlorogenic acid-type caffeoylquinic acids (chlorogenic and di-caffeoylquinic acids) given orally at 10–20 mg/kg reduced ammonia-induced cough and increased phenol-red expectoration ^{5Reference 5Wu et al. · 2016AnimalAntitussive, expectorant, and anti-inflammatory activities of four caffeoylquinic acids isolated from Tussilago farfara — mouse in vivoView study →}, and bioactivity-guided and metabolomic profiling identified these caffeoylquinic acids and sesquiterpenes as the constituents carrying the antitussive/expectorant activity of the flower bud ^{6,7,8Reference 6Discovering the major antitussive et al. · 2020In vitrohttps://pubmed.ncbi.nlm.nih.gov/32023945/View study →Reference 7Li et al. · 2012AnimalMetabolomic profiling of the flower bud and rachis of Tussilago farfara with antitussive and expectorant effects — animal model. (2012). https://pubmed.ncbi.nlm.nih.gov/22210102/View study →Reference 8Metabolomic profiling of the antitussive et al. · 2013https://pubmed.ncbi.nlm.nih.gov/23261808/View study →}. Mechanistically, tussilagone suppresses production and gene expression of MUC5AC — a major airway mucin — which is consistent with an expectorant/mucoregulatory action ^{9Reference 9Choi et al. · 2018In vitroTussilagone suppressed the production and gene expression of MUC5AC mucin — in vitro airway modelView study →}.

Gap: all data are rodent or cell-based; there is no controlled human cough trial, and the classic “smoked as herbal tobacco” route has no supporting efficacy evidence.

3. Respiratory / lung-protective

Beyond cough, coltsfoot constituents are protective in several rodent lung-injury models. An ethanol extract of the flower buds attenuated cigarette-smoke-induced lung inflammation in mice by regulating the NLRP3 inflammasome, Nrf2 and NF-κB ^{17Reference 17Li et al. · 2022In vitroThe ethanol extract of flower buds of Tussilago farfara L. attenuates cigarette-smoke-induced lung inflammation through NLRP3 inflammasome, Nrf2, and NF-κB — mouse in vivo / in vitroView study →}, and tussilagone attenuated cigarette-smoke COPD by covalently modifying cysteine-434 of KEAP1 to activate Nrf2 ^{18Reference 18Tussilagone attenuated cigarette-smoke-i · 2026AnimalJournal of Advanced Research. https://pubmed.ncbi.nlm.nih.gov/40669599/View study →}, protected against PM2.5-induced acute lung injury via the Hif-1α/NF-κB axis ^{19Reference 19Tussilagone protects acute lung injury f · 2022In vitroEnvironmental Toxicology. https://pubmed.ncbi.nlm.nih.gov/35112795/View study →}, and improved survival and reduced lung injury in sepsis models ^{20,22Reference 20Tussilagone mitigates sepsis-induced acu · 2026Animalhttps://pubmed.ncbi.nlm.nih.gov/42015326/View study →Reference 22Tussilagone inhibits the inflammatory re et al. · 2017Animalhttps://pubmed.ncbi.nlm.nih.gov/29258263/View study →}. A metabolomic study links the caffeoylquinic acids to the lung-protective effect ^{21Reference 21Farfarae Flos mitigates cigarette-smokin et al. · 2025AnimalBiomedical Chromatography. https://pubmed.ncbi.nlm.nih.gov/39775926/View study →}.

Gap: most of the strongest work uses isolated tussilagone, frequently by intraperitoneal injection, so it speaks to the molecule more than to a leaf infusion; no human respiratory-disease data exist.

4. Antioxidant (Nrf2 cytoprotection)

Coltsfoot’s antioxidant action is mechanistically specific rather than merely a radical-scavenging assay result. The analogue tussilagonone activates Nrf2 and up-regulates the detoxifying enzymes NQO1 and HO-1, protecting HepG2 cells from oxidative injury ^{23Reference 23Lee et al. · 2017In vitroTussilagonone-induced Nrf2 pathway activation protects HepG2 cells from oxidative injury — in vitroView study →}. Quercetin glycosides isolated from the flower buds raised cellular glutathione and induced γ-glutamylcysteine ligase through the Nrf2/ARE pathway ^{24Reference 24Kim et al. · 2006In vitroAntioxidative effects of quercetin-glycosides isolated from the flower buds of Tussilago farfara L. — in vitroView study →}, and an ethyl-acetate fraction blocked oxidative neuronal damage from H2O2 and other oxidants ^{25Reference 25Cho et al. · 2005In vitroNeuroprotective and antioxidant effects of the ethyl acetate fraction prepared from Tussilago farfara L. — in vitroView study →}. Comparative phytochemical work confirms measurable antioxidant capacity tracking the phenolic content ^{26Reference 26A comparative analysis of the anatomy et al. · 2022In vitrohttps://pubmed.ncbi.nlm.nih.gov/35807614/View study →}.

Gap: almost entirely in-vitro/cell-based; antioxidant assays do not establish a clinical antioxidant effect, and the Nrf2-inducing compounds overlap with those studied as isolated molecules.

5. Neuroprotective

Several models point to neuroprotection through the same antioxidant/anti-inflammatory machinery. An ethyl-acetate fraction protected primary rat cortical neurons against amyloid-β, glutamate/NMDA excitotoxicity and oxidative insult ^{25Reference 25Cho et al. · 2005In vitroNeuroprotective and antioxidant effects of the ethyl acetate fraction prepared from Tussilago farfara L. — in vitroView study →}; isolated sesquiterpenoids reduced LPS-induced microglial activation and downstream neuronal death via NF-κB inhibition ^{12Reference 12Lim et al. · 2015In vitroIn vitro neuroprotective activity of sesquiterpenoids from the flower buds of Tussilago farfara — in vitroView study →}; a sesquiterpenoid protected PC12 cells and mice against 6-OHDA (a Parkinson’s model) through Nrf2 ^{27Reference 27Lee et al. · 2018In vitroNeuroprotection against 6-OHDA toxicity in PC12 cells and mice through the Nrf2 pathway by a sesquiterpenoid from Tussilago farfara — in vivo / in vitroView study →}; and a flower-bud extract reduced infarct size and microglial inflammation in a rat middle-cerebral-artery-occlusion stroke model ^{28Reference 28Effects of flower buds extract of Tussil et al. · 2018Animalhttps://pubmed.ncbi.nlm.nih.gov/30090976/View study →}.

Gap: rodent and cell models only, several using isolated compounds; no cognitive or neurological human data.

6. Anticancer (antiproliferative)

Preclinical antiproliferative signals exist across several tumour types. Tussilagone promotes β-catenin degradation and suppresses colon-cancer cell proliferation ^{29Reference 29Li et al. · 2014In vitroTussilagone suppresses colon cancer cell proliferation by promoting the degradation of β-catenin — in vitroView study →}, inhibits triple-negative breast-cancer cell growth and EMT via the TLR4/NF-κB pathway ^{30Reference 30Tussilagone suppresses triple-negative b · 2025In vitroImmunopharmacology and Immunotoxicology. https://pubmed.ncbi.nlm.nih.gov/41029481/View study →}, sensitises hepatocellular-carcinoma cells to TRAIL-induced apoptosis ^{31Reference 31Tussilago farfara L · 2014In vitroOncology Reports. https://pubmed.ncbi.nlm.nih.gov/24969837/View study →}, suppresses angiogenesis through VEGFR2 ^{32Reference 32Tussilagone suppresses angiogenesis by i · 2019In vitrohttps://pubmed.ncbi.nlm.nih.gov/31333473/View study →}, and reduces tumour burden in a colitis-associated colon-cancer mouse model ^{33Reference 33Tussilagone reduces tumorigenesis by dim · 2020Animalhttps://pubmed.ncbi.nlm.nih.gov/32290483/View study →}. This indication carries an internal contradiction worth stating plainly: the whole herb is itself hepatocarcinogenic in rodents through its pyrrolizidine alkaloids ^{43Reference 43Hirono et al. · 1976AnimalCarcinogenic activity of coltsfoot, Tussilago farfara L. — rat in vivoView study →}, so any “anticancer” reading applies to purified constituents, not the plant.

Gap: cell lines and one mouse model; the herb’s own carcinogenicity makes whole-plant anticancer use untenable.

7. Anti-allergic

Tussilagone reduced allergic-rhinitis symptoms and serum histamine, IgE and cytokines in an ovalbumin-sensitised guinea-pig model and stabilised IgE-stimulated mast cells ^{34Reference 34Tussilagone inhibits allergic responses et al. · 2020In vitroFitoterapia. https://pubmed.ncbi.nlm.nih.gov/32058052/View study →}, and a 2026 study shows it inhibits MRGPRX2-mediated mast-cell degranulation, suppressing pseudo-allergic (non-IgE) reactions ^{35Reference 35Tussilagone inhibits MRGPRX2-mediated ma et al. · 2026In vitrohttps://pubmed.ncbi.nlm.nih.gov/41707990/View study →}.

Gap: two isolated-compound studies in one animal species and cell lines; no human allergy data.

8. Metabolic / anti-diabetic

Signals here are constituent-level and early. Flower-bud extracts inhibit aldose reductase, an enzyme implicated in diabetic complications ^{36Reference 36Identification of aldose reductase inhib · 2025In vitroJournal of Chromatography A. https://pubmed.ncbi.nlm.nih.gov/40117791/View study →}; tussilagone reduced high-fat-diet hepatic steatosis in mice by enhancing energy metabolism and antioxidant activity ^{37Reference 37Tussilagone ameliorates high-fat-diet-in et al. · 2024In vitroPhytotherapy Research. https://pubmed.ncbi.nlm.nih.gov/37010930/View study →}; and newly isolated sesquiterpenoids enhanced insulin-stimulated glucose uptake in C2C12 myotubes via IRS-1/Akt/GSK-3β ^{16Reference 16Sesquiterpenoids from Tussilago farfara: et al. · 2026In vitroChinese Journal of Natural Medicines. https://pubmed.ncbi.nlm.nih.gov/41781124/View study →}.

Gap: in-vitro enzyme and cell assays plus a single NAFLD mouse model; no glycaemic human data.

9. Cardiovascular

Tussilagone inhibits platelet activation by blocking GPVI downstream signalling in vitro ^{38Reference 38Antiplatelet activity of tussilagone via · 2020In vitroPlatelets. https://pubmed.ncbi.nlm.nih.gov/32850895/View study →} and attenuated atherosclerotic lesion formation in ApoE-deficient mice by suppressing MAPK-mediated macrophage inflammation ^{39Reference 39Tussilagone attenuates atherosclerosis t · 2023AnimalInternational Immunopharmacology. https://pubmed.ncbi.nlm.nih.gov/37058752/View study →}.

Gap: one in-vitro platelet study and one mouse model; an antiplatelet signal is also a theoretical bleeding-interaction concern rather than a validated benefit.

10. Antimicrobial

In-vitro screens report modest antibacterial activity for coltsfoot extracts and essential oil ^{40,41Reference 40Chemical composition et al. · 2020In vitroNatural Product Research. https://pubmed.ncbi.nlm.nih.gov/30257572/View study →Reference 41Screening of some Siberian medicinal pla · 2002In vitrohttps://pubmed.ncbi.nlm.nih.gov/12169406/View study →}, and Flos Farfarae preparations inhibited enterovirus 71 replication in cell culture ^{42Reference 42Flos Farfarae inhibits enterovirus 71-in · 2017In vitrohttps://pubmed.ncbi.nlm.nih.gov/28231741/View study →}.

Gap: most antibacterial data come from the essential oil — a preparation the herb is not traditionally taken as — and potencies are modest; no in-vivo infection data.

Mechanisms

Mechanism	Drives	Key compounds
NF-κB ↓, MAPK ↓, Nrf2/HO-1 ↑, KEAP1-Cys434 modification, NO/TNF-α/PGE2 ↓	anti-inflammatory, respiratory, antioxidant, neuroprotective, anticancer	tussilagone, tussilagonone
Cough-reflex suppression, mucin (MUC5AC) regulation, phenolic antioxidant	antitussive, expectorant, lung-protective	chlorogenic acid, dicaffeoylquinic acids
Radical scavenging; Nrf2/ARE → glutathione ↑	antioxidant, cytoprotective	quercetin, kaempferol, rutin, isoquercitrin
Physical demulcent coating; immunomodulatory in vitro	demulcent, soothing (traditional)	mucilage polysaccharides
Hepatic metabolism to reactive pyrroles → DNA/protein adducts	hepatotoxicity, carcinogenicity (harm, not benefit)	senkirkine, senecionine

Clinical trials

No registered clinical trials evaluate coltsfoot as a single-herb intervention for any efficacy indication — a ClinicalTrials.gov search returns only studies where coltsfoot appears incidentally within a multi-ingredient product, not as the agent under test, so the efficacy evidence base is entirely preclinical.

Completed	Planned	Terminated	Preclinical
0	0	0	~60–80

Last checked: July 2026.

Safety

Coltsfoot contains unsaturated pyrrolizidine alkaloids (chiefly senkirkine and senecionine) that are hepatotoxic and pro-carcinogenic; hepatic metabolism converts them to reactive pyrroles that form DNA and protein adducts ^{43,45Reference 43Hirono et al. · 1976AnimalCarcinogenic activity of coltsfoot, Tussilago farfara L. — rat in vivoView study →Reference 45Sensitive determination of pyrrolizidine et al. · 2016Journal of Separation Science. https://pubmed.ncbi.nlm.nih.gov/27673325/View study →}. This bioactivation step is why the alkaloids are both liver-toxic and carcinogenic, and why intermittent low-dose exposure still accumulates risk. A long-term rodent feeding study of pre-blooming coltsfoot flowers produced hepatic haemangioendothelial sarcomas, attributed to senkirkine ^{43Reference 43Hirono et al. · 1976AnimalCarcinogenic activity of coltsfoot, Tussilago farfara L. — rat in vivoView study →} — one of the only whole-herb in vivo toxicology studies of the plant. Human evidence is limited to case reports of hepatic veno-occlusive disease — including a fatal infantile case — associated with coltsfoot ingestion, though a systematic review found species misidentification and substitution frequently compromised these reports and cautioned against over-attribution ^{44Reference 44A systematic review et al. · 2020Systematic reviewFitoterapia. https://pubmed.ncbi.nlm.nih.gov/32105669/View study →}. Alkaloid content is low and highly variable (typically <0.015% of dried herb) and depends on plant part, chemotype and region ^{2,45Reference 2Adamczak et al. · 2013Content of pyrrolizidine alkaloids in the leaves of coltsfoot (Tussilago farfara L.) in Poland — analyticalView study →Reference 45Sensitive determination of pyrrolizidine et al. · 2016Journal of Separation Science. https://pubmed.ncbi.nlm.nih.gov/27673325/View study →}; PA-free cultivars exist, but a low average content does not guarantee a low dose in any given sample. As a daisy-family plant, coltsfoot also carries the general Asteraceae cross-sensitivity caution relevant to those who react to ragweed, chamomile and related plants. Internal use is restricted or discouraged in several countries — PA-containing herbs are subject to strict daily-intake limits under EMA/HMPC and various national regulators — and should be avoided in pregnancy, lactation, liver disease, and for prolonged periods. Given safer alternatives for coughs, internal use of ordinary coltsfoot is best avoided.

Scope: interactions were only partially assessed. An in-vitro antiplatelet effect of tussilagone (GPVI inhibition) ^{38Reference 38Antiplatelet activity of tussilagone via · 2020In vitroPlatelets. https://pubmed.ncbi.nlm.nih.gov/32850895/View study →} raises a theoretical bleeding-risk interaction with anticoagulant or antiplatelet drugs, but no clinical drug-interaction study exists, and no CYP450 interaction has been formally evaluated — treat both as theoretical, not established. The pregnancy contraindication rests on pyrrolizidine-alkaloid placental transfer and case-report harm, not on a controlled pregnancy safety study. Absence of a large adverse-event volume reflects limited use under restriction, not established safety.

Pregnancy & lactation

Avoid. Pyrrolizidine alkaloids cross the placenta and are linked to a fatal infantile hepatic veno-occlusive-disease case ^{44Reference 44A systematic review et al. · 2020Systematic reviewFitoterapia. https://pubmed.ncbi.nlm.nih.gov/32105669/View study →}; coltsfoot should not be used internally during pregnancy or breastfeeding. This is a precautionary pharmacopoeial contraindication, not a conclusion from a pregnancy safety trial.

References

1. Chen, S., et al. (2021). A review of the ethnobotanical value, phytochemistry, pharmacology, toxicity and quality control of Tussilago farfara L. (coltsfoot) — review. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/33069788/
2. Adamczak, A., Opala, B., Gryszczyńska, A., & Buchwald, W. (2013). Content of pyrrolizidine alkaloids in the leaves of coltsfoot (Tussilago farfara L.) in Poland — analytical. Acta Societatis Botanicorum Poloniae. https://doi.org/10.5586/asbp.2013.028
3. Liu, C., et al. (2020). Farfarae Flos: a review of botany, traditional uses, phytochemistry, pharmacology, and toxicology — review. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/32526340/
4. Coltsfoot (Tussilago farfara): a review — review. (2025). Natural Product Research. https://pubmed.ncbi.nlm.nih.gov/40892112/
5. Wu, Q. Z., et al. (2016). Antitussive, expectorant, and anti-inflammatory activities of four caffeoylquinic acids isolated from Tussilago farfara — mouse in vivo. Pharmaceutical Biology. https://pubmed.ncbi.nlm.nih.gov/26439905/
6. Discovering the major antitussive, expectorant, and anti-inflammatory bioactive constituents in Farfarae Flos — animal / in vitro. (2020). https://pubmed.ncbi.nlm.nih.gov/32023945/
7. Li, Z. Y., et al. (2012). Metabolomic profiling of the flower bud and rachis of Tussilago farfara with antitussive and expectorant effects — animal model. (2012). https://pubmed.ncbi.nlm.nih.gov/22210102/
8. Metabolomic profiling of the antitussive and expectorant plant Tussilago farfara L. by NMR — analytical. (2013). https://pubmed.ncbi.nlm.nih.gov/23261808/
9. Choi, B. S., et al. (2018). Tussilagone suppressed the production and gene expression of MUC5AC mucin — in vitro airway model. Korean Journal of Physiology & Pharmacology. https://pubmed.ncbi.nlm.nih.gov/30402027/
10. Hwangbo, C., et al. (2009). The anti-inflammatory effect of tussilagone, from Tussilago farfara, is mediated by the induction of heme oxygenase-1 in murine macrophages — in vitro. International Immunopharmacology. https://pubmed.ncbi.nlm.nih.gov/19800419/
11. Cheon, H. J., et al. (2018). Tussilagone ameliorates inflammatory responses in dextran-sulphate-sodium-induced murine colitis — mouse in vivo. Chemico-Biological Interactions. https://pubmed.ncbi.nlm.nih.gov/30142311/
12. Lim, H. J., et al. (2015). In vitro neuroprotective activity of sesquiterpenoids from the flower buds of Tussilago farfara — in vitro. Journal of Enzyme Inhibition and Medicinal Chemistry. https://pubmed.ncbi.nlm.nih.gov/25291008/
13. Sesquiterpenoids from Tussilago farfara and their inhibitory effects on nitric oxide production — in vitro. (2014). https://pubmed.ncbi.nlm.nih.gov/24963619/
14. Lee, J., et al. (2020). Tussilagonone ameliorates psoriatic features in keratinocytes and imiquimod-induced psoriasis-like skin inflammation — mouse in vivo. https://pubmed.ncbi.nlm.nih.gov/31877316/
15. Prunella vulgaris and Tussilago farfara demonstrate anti-inflammatory activity in rabbits and protect human adipose stem cells against thermal stress in vitro — animal / in vitro. (2025). Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/39442825/
16. Sesquiterpenoids from Tussilago farfara: full structure elucidation, anti-diabetic and anti-inflammatory signalling pathways — in vitro. (2026). Chinese Journal of Natural Medicines. https://pubmed.ncbi.nlm.nih.gov/41781124/
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