How does it feel?
An infusion made with the dried leaf and flower makes a dark green tea, which smells salty and reminiscent of the sea. The taste is slightly salty, savoury, bitter and mildly sweet. The texture is mucilaginous and then transforms to astringent, leaving a really dry sensation in the mouth and throat after a few minutes. The slight sweetness and the mucilaginous sensation expresses the polysaccharide constituents, and the bitterness reveals the terpenes. The astringency is indicative of the tannin content and the saltiness communicates the mineral content. If there is any phlegm lurking in the sinuses and lungs causing you to feel foggy, stagnant, and lethargic, this will be gradually shifted over the rest of the day, leaving you feeling more clear headed and motivated.
What can I use it for?
Coltsfoot is an excellent herb for a dry, irritating, tickly cough. The anti-tussive action will help to stop the cough, and the mucilaginous constituents will provide soothing, anti-inflammatory relief to the throat and lungs. Coltsfoot can also be used for chronic lung conditions such as asthma or chronic obstructive pulmonary disease (COPD) where the lungs have become chronically congested and need some support and rejuvenation.
Safety note: Some caution is warranted when using this herb as it contains potentially toxic constituents called pyrrolizidine alkaloids (PAs). The risks of exposure are mild due to the low concentration of PAs in coltsfoot, however, regular or excessive consumption of coltsfoot, especially in the form of herbal teas, should be avoided (1). See the section on safety (below) before consuming coltsfoot in herbal formulas.
Into the heart of coltsfoot
There are some conflicting opinions about the energetics of coltsfoot as it is categorised by some as cooling (2,3) and by others as warming (4). However, this difference of opinion could be explained by the preparation of the herb, since the fresh herb is cooling, whereas the dried herb is more heating (5).
There is, however, agreement that it is both moistening and drying, depending on the condition being treated (2,3,4,6). In conditions of excessive mucus, coltsfoot will thicken and dry the phlegm and astringe the mucous membranes, whereas dry conditions can be supported by the mucilaginous polysaccharides.
Coltsfoot contains some constituents in the category of pyrrolizidine alkaloids (PAs), of which there are around 650 different kinds (7). Although PAs are often collectively considered to be toxic, there is a varying degree of toxicity in these constituents from mild to significant, and some are entirely non-toxic (7). During the process of breakdown in the liver some types of PAs are converted to toxic byproducts, which can damage the hepatic tissue (8). The main PAs in coltsfoot are the non-toxic tussilagine, tussilaginine, isotussilagine and isotussilagine (7). However, it also contains small amounts of the toxic senkirkine (0.015%) and trace amounts of the toxic senecionine (0.001%) (7).
The concentrations of PAs in coltsfoot are thought to be too low to be clinically significant, although the dangers associated with long-term use, even at low doses, are unclear (1). No cases of human toxicity have been linked to the use of coltsfoot at the recommended dosages (1,7). Two case reports of toxicity were later determined to be misidentification of a Senecio species as coltsfoot, and a combination of other PA-containing herbs ingested at the same time (9). In animal studies exploring toxicity, rats had to be exposed to very high doses of coltsfoot (more than 4% of their diet) before they developed liver damage. To give context to this, one cup of coltsfoot infusion will contain one part-per-million (PPM*) of total PAs, which is an extremely low exposure (7). PAs are water soluble and will be more highly concentrated in water extracts, whereas oil extracts contain lower concentrations of the potentially toxic PA constituents (7).
* One PPM equates to one microgram (mcg) per gram (5).
Traditional uses
Culpeper’s Complete Herbal states that the fresh leaves or juice are cooling and drying, and to be used for a hot, dry cough, wheezing and shortness of breath (10). The dried leaves or roots were considered hot and dry, and used as a tea or smoked as a good remedy for those with “thin rheums [watery discharges] and distillations [mucus] upon their lungs” (10). Externally, wet clothes soaked in coltsfoot distilled water were applied to hot swellings, inflammation, skin wheals, burns and the “burning heat of piles or privy parts” (10). Every part of the plant was used medicinally, but more often the leaves (11). The leaves were the principal ingredient in the British erbobacco, and the smoking of this plant dates back to Dioscorides, Galen, Pliny and Boyle (11, 12). British herb tobacco also contained b buckbean, eyebright (Euphrasia officinalis), betony (Betonica officinalis), rosemary (Rosmarinus officinalis), thyme (Thymus vulgaris), lavender (Lavandula angustifolia), and chamomile (Matricaria chamomilla), and was used to relieve asthma, bronchitis, catarrh and difficulty breathing (12).
Felter reported coltsfoot to be an emollient, demulcent, and tonic, used to relieve irritation of the mucous tissues (13). A decoction was used for coughs, asthma, whooping-cough, laryngitis, pharyngitis, bronchitis, scrofula and in gastric and intestinal catarrh (13). The powdered leaves were used to induce sneezing or increase nasal excretions and used for giddiness, headache, nasal obstructions (13). It was used externally in the form of a poultice or, a tincture of the leaves and the flowers, given in doses of 1 to 10 drops for scrofulous tumours (13).
Grieve described coltsfoot as one of the most popular cough remedies, describing it as “nature’s best herb for the lungs and her most eminent thoracic” (12). Coltsfoot wine was considered excellent for all pulmonary diseases, “to be taken at all times when there is diseases of the lungs, its influence more apparent when inflammation is present” (5). It was generally given together with other herbs such as horehound (Marrubium vulgare), marshmallow (Althaea officinalis) and ground ivy (12).
Traditional actions
Herbal actions describe therapeutic changes that occur in the body in response to taking a herb. These actions are used to express how a herb physiologically influences cells, tissues, organs or systems. Clinical observations are traditionally what have defined these actions: an increase in urine output, diuretic; improved wound healing, vulnerary; or a reduction in fever, antipyretic. These descriptors too have become a means to group herbs by their effects on the body — herbs with a nervine action have become the nervines, herbs with a bitter action are the bitters. Recognising herbs as members of these groups provides a preliminary familiarity with their mechanisms from which to then develop an understanding of their affinities and nuance and discern their clinical significance.
Traditional energetic actions
Herbal energetics are the descriptions Herbalists have given to plants, mushrooms, lichens, foods, and some minerals based on the direct experience of how they taste, feel, and work in the body. All traditional health systems use these principles to explain how the environment we live in and absorb, impacts our health. Find out more about traditional energetic actions in our article “An introduction to herbal energetics“.
What practitioners say
Respiratory
Coltsfoot is an approved herb of the American Botanical Council, with the Commission E monograph stating uses for “acute catarrh of the respiratory tract with cough and hoarseness; acute, mild inflammation of the oral and pharyngeal mucosa” (14).
Coltsfoot is an excellent herb for a dry, irritating, non-productive cough. The flavonoids in coltsfoot have anti-inflammatory, anti-spasmodic, and antitussive actions which help to relax the muscles in the respiratory system, soothing bronchial spasms and easing the cough (15, 16). This can be helpful in whooping cough or a dry cough in asthmatic conditions to halt the spasming action of the lungs. Other herbs with anti-tussive and antispasmodic action to consider as an alternative to coltsfoot include cherry bark, pleurisy root (Asclepias tuberosa), wild lettuce (Lactuca virosa) and hyssop (Hyssopus officinalis). However, anti-tussive herbs are not suitable for damp, productive coughs as mucus can get stuck in lungs, allowing infection to develop. When treating a dry, irritating cough, antitussive herbs are best combined with other ingredients to support the lung tissue such as mullein (Verbascum thapsus), white horehound, plantain (Plantago lanceolata), marshmallow and liquorice (Glycyrrhiza glabra).
Coltsfoot is high in polysaccharides, which are anti-inflammatory, immune-stimulating and demulcent (16). The anti-inflammatory mucilage can soothe and protect inflamed and irritated mucous membranes (15). This is helpful where there is pain and inflammation in the throat, airways or lungs from a persistent cough, laryngitis, tonsillitis or asthma. Herbal alternatives to coltsfoot with soothing, demulcent and anti-inflammatory actions on the lungs include marshmallow leaf and root, pleurisy root, liquorice, and mullein.
Coltsfoot works well as a remedy for individuals with chronic, debilitating lung conditions such as asthma, silicosis, chronic bronchitis or emphysema, and those with lung damage from smoking (2, 5, 17). The condition often becomes chronic with deep, dried mucus that is difficult to expel, and the lungs may be damaged by scar tissue (3). The active constituents support recovery of the bronchial cilia, restore the integrity of the respiratory mucosa and increase immune resistance which can provide relief from the exhausted condition (2,3). These conditions are often accompanied by constricted airways and trapped mucus, in which coltsfoot dilates the bronchi and loosens stagnation, making it easier to cough up any phlegm (18).
Coltsfoot has anti-oxidant and anti-bacterial actions, however alternative herbs with these actions specific to the lungs include elecampane (Inula helenium), thyme and aniseed (Pimpinella anisum).
Gastrointestinal tract (GIT)
Due to the mucilage content of coltsfoot, it has a demulcent action which can be used to soothe irritations in the GIT and treat inflammatory digestive disorders, especially where there is ulceration (15). One of the major constituents of coltsfoot, tussilagone, has strong anti-inflammatory activity by inhibiting the activation of tumour necrosis factor (TNF)-α, TNF-κB and interleukin-6 (19). This has been demonstrated in vivo to attenuate colonic inflammatory damage in intestinal colitis (19).
External
The fresh, bruised leaves can be applied to boils, abscesses, and suppurating ulcers (15). A poultice of the flowers can soothe and support healing of inflamed skin disorders such as eczema, ulcers, sores, varicose veins and insect bites (18, 20). The antiseptic and skin toning properties can be used to minimise blemishes and reduce skin oiliness when used in a facial steam or toner (4).
Research
There is a lack of research exploring the use of coltsfoot in human clinical trials. One study included coltsfoot as an ingredient in a multi-herb decoction in the treatment of 35 asthmatic patients (21). All patients were in convalescence and had obstruction of the airways, defined by lower-than-normal values on pulmonary function assessments. The decoction of several Chinese herbs (Viscum coloratum 15 g, Psoralea corylifolia 15 g, Eucommia ulmoides 15 g, Lycium chinense 9 g, Tussilago farfara 15 g, Artemisia capillaris 9 g, and Pogostemon cablin 9 g), was given daily for 10 weeks to all the patients. After the 10 weeks, maximal expiratory flow-volume curve (MEFV) was significantly improved, suggesting that the airway obstruction of asthmatics in the convalescent stage is reversible with herbal therapy (21).
Did you know?
In Paris, the coltsfoot flower used to be painted as a sign on the door of apothecary shops (12).
Additional information
Botanical description
Coltsfoot is a low-growing, rhizomatous perennial plant, flowering from February to May, before the leaves emerge from April to November (26,27). The flowers are yellow with both disk and ray florets (15–35 mm), atop a single stem (28). The stems are short, purplish, white, woolly and leafless with many overlapping, fleshy scales, growing to a height of 10–15 cm (27,28). The leaves are broadly heart-shaped, polygonal, resembling a colt’s foot, entire and toothed with a grey tinge of downy on the upper side (10,27,28). It produces copious white pappus seeds, similar to dandelions (27,28). It spreads by seed and fleshy but brittle rhizomes (27). The rhizomes bury deep and preserve their vitality for a long time, and may spring up when the ground is disturbed (12).
Common names
- Ass’s foot
- Bull foot
- Clay weed
- Colt herb
- Common colt’s foot
- Coughwort
- Dove dock
- Dummy weed
- Foal foot
- Ginger
- Hoofs
- Horse foot
- Horse hoof
- Sow foot
- Tushy luck
- Cleats
- Cleets
- Foal’s foot
- British tobacco
Safety
Coltsfoot contains potentially hepatotoxic pyrrolizidine alkaloids (PA), especially the flowers (22). Since the discovery of PAs, which can cause veno-occlusive liver disease in susceptible individuals, the traditional herbal use of the coltsfoot has come into question (23). Prolonged use and high doses should be avoided and limited to 4–6 weeks use per year (2, 14, 22).
The European Medicines Agency recommends the maximum duration of two weeks of continuous use (24).
In Australasia, coltsfoot cannot be legally prescribed for internal use (24).
Avoid during pregnancy due to potential abortifacient effects and the hepatotoxic pyrrolizidine alkaloids, which can be fatal to the foetus (22). Coltsfoot should not be consumed when breastfeeding due to the hepatotoxic pyrrolizidine alkaloids (22). Coltsfoot should not be taken by children under the age of 18 years old (5). The use of coltsfoot is recommended under the guidance of a qualified medical herbal professional.
Interactions
Coltsfoot should not be taken at the same time as herbs or medications which induce CYP3A, including St John’s Wort (Hypericum perforatum), schisandra (Schisandra chinensis) and epilepsy medications (5). Induction of phase one liver metabolism (specifically CYP3A), speeds the conversion of PAs to the activated toxic pyrroles (5,8). Conjugation of the pyrroles in phase two liver metabolism is the rate-limiting step of detoxification, and induction of phase one metabolism increases the potential for hepatic cell injury (8).
Coltsfoot should not be taken alongside other medications requiring phase two liver metabolism, especially those requiring glutathione conjugation, since PA-induced hepatotoxicity may be more pronounced if the glutathione content in the liver is low (8).
Due to the risk of additive toxicity, coltsfoot should not be taken alongside other PA-containing herbs or supplements, including boneset, borage, butterbur, comfrey, gravel root, hemp agrimony, and tansy (25).
Contraindications
Coltsfoot should be avoided or only taken under the guidance of a medical herbalist if there is profuse congestion of catarrh of the mucous membranes, since the mucilage may exaggerate the effect of the mucosal discharge (22). Coltsfoot should not be used by anyone with a history of liver disease due to the potential hepatotoxicity from the pyrrolizidine alkaloids (22).
Preparations
- Infusion (Tea)
- Tincture
- Syrup
The flowers contain the highest concentration of pyrrolizidine alkaloids, and there is considerable loss of these constituents with drying (1). It is, therefore, recommended to use dried leaf for water extract preparations (1). The leaves can be collected and used when fully grown, throughout spring, summer and into autumn (15).
Dosage
- Tincture (1:5 | 45%): 2–8 ml, three times per day (1, 15, 17)
- FE (1:1 extract): 0.6–2 ml, three times a day (1)
- Infusion: 0.6–2 g (1–2 teaspoon) dried leaf, three times per day (1, 15, 17), up to a maximum of 10 g per day (14)
- Syrup: 2–8 ml (1:4 liquid extract to syrup), three times per day (1)
- Topical: 5–10% ointment (14)
The daily dose of pyrrolizidine alkaloids should not exceed 100 mcg per day (15, 24).
Given the potential safety concerns of PA consumption (outlined above), the lowest effective dose should be used (5).
Plant parts used
- Leaf
- Flower
Constituents
- Pyrrolizidine a lkaloids (0.5–73 mcg per gram): Tussilagine (non-toxic), senkirkine (0.015%) and senecionine (0.00001– 0.001%) (1, 5, 7)
- Polysaccharides: Mucilage (7– 8%); inulin (1)
- Flavonoids: Kaempferol, quercetin, rutin, (1, 15)
- Tannins: Up to 17% (1)
- Acids: Caffeic acid, caffeoyltartaric acid, ferulic acid, gallic acid, p-hydroxybenzoic acid, and tannic acid (phenolic); malic acid and tartaric acid (1)
- Terpenes: Bitter (glycoside), triterpenes (amyrin, bauerenol), sesquiterpenes (tussilagone, bisbolene epoxide, farfaratin) (1, 14)
- Phytosterols: Sitosterol, stigmasterol, taraxasterol (1, 17)
- Other constituents: Holine; volatile oil; zinc; magnesium; potassium; calcium; vitamins A, B6, B12, C; (1, 4, 14, 17, 29)
Habitat
Coltsfoot is native to Europe, North Africa and Nepal, and has been introduced across North America and Australasia (29,30). It is a perennial and common wild plant, growing primarily in the temperate biome (16,29). Coltsfoot can be found in a wide range of habitats from moist or dry, often on disturbed grounds including poorly drained clay, sand dunes, arable land, shingle, cliff-slopes, landslides, spoil heaps, seepage areas, rough grassland, crumbling riverbanks, waste places, railway banks and roadside verges (12,26).
Sustainability
Coltsfoot is listed as least concern, and not listed on CITES or United Plant Savers list of threatened species (30,31,32,33,34). Coltsfoot is not currently threatened by extinction (29), and is not subject to any trading restriction (31).
The International Union for Conservation of Nature (30) have globally assessed coltsfoot and list it as “Least Concern”. They state that the species is widely distributed across Europe, temperate and tropical Asia, and North America (30). Coltsfoot is a very common species with a large and stable population, often regarded as a weed (30).
On the Plant Red Data List for Great Britain, coltsfoot is categorised as Least Concern (LC) (34). A taxon is Least Concern when it has been evaluated against the criteria and does not qualify for Critically Endangered, Endangered, Vulnerable or Near Threatened. Widespread and abundant taxa are included in this category (34).
Habitat loss and over-harvesting from the wild are two of the biggest threats faced by medicinal plant species. There are an increasing number of well-known herbal medicines at risk of extinction. We must, therefore, ensure that we source our medicines with sustainability in mind.
The herb supplement industry is growing at a rapid rate and until recent years a vast majority of medicinal plant produce in global trade was of unknown origin. There are some very real and urgent issues surrounding sustainability in the herb industry. These include environmental factors that affect the medicinal viability of herbs, the safety of the habitats that they are taken from, as well as the welfare of workers in the trade.
The botanical supply chain efforts for improved visibility (transparency and traceability) into verifiably sustainable production sites around the world is now certificated through the emergence of credible international voluntary sustainability standards (VSS).
Read our article on Herbal quality and safety: What to know before you buy and Sustainable sourcing of herbs to learn more about what to look for and questions to ask suppliers about sustainability.
Quality control
Herbal medicines are often very safe to take; however, their safety and efficacy can be jeopardised by quality issues. So, it is important to buy herbal medicines from a reputable supplier, from sources known to test their herbs to ensure there is no contamination, adulteration or substitution with incorrect plant matter, as well as ensuring that recognised marker compounds are at appropriate levels in the herbs.
Some important quality assurances to look for are certified organic labelling, the correct scientific/botanical name, and the availability of information from the supplier about ingredient origins. A supplier should be able to tell you where the herbs have come from, what contaminants are not in the herb, and what the primary compounds are.
How to grow
Coltsfoot can be propagated by seed or rhizome, but spreads year-on-year via the rhizomes so can become a perennial nuisance once planted in the garden (27). No pruning is required as the deciduous leaves die back each year and new growth appears the following spring (27).
Recipe
Herbal smoking mix
This can be used as an alternative to tobacco smoking, and used to support those who are trying to quit smoking.
Ingredients
- 15 g dried coltsfoot leaf
- 10 g dried mullein leaf
- 10 g dried mugwort leaf and flower
- 10 g dried marshmallow leaf
- 5 g dried peppermint leaf
Method
Blend all the dried herbs to break down to a suitable consistency for use in a smoking pipe or rolling papers. For support with smoking cessation, gradually replace the tobacco with the smoking mix.
References
- Barnes, J., Anderson, L.A. and Phillipson, J.D. Herbal medicines: a guide for healthcare professionals: Third Edition. Pharmaceutical press; 2007.
- Easley T, Horne S. The Modern Herbal Dispensatory: A Medicine-Making Guide. North Atlantic Books; 2016.
- Wood M. The Earthwise Herbal Volume 1: A Complete Guide to New World Medicinal Plants. North Atlantic Books; 2008.
- Mars, B. The Desktop Guide to Herbal Medicine. Basic Health Publications Inc; 2007.
- Tobyn, G., Denham, A., Whitelegg, M., Kingsbury, S. & Rowling, M. The Western Herbal Tradition: 2000 Years of Medicinal Plant Knowledge: Jessica Kingsley Publishers; 2016.
- Jones, L. A Working Herbal Dispensary: respecting herbs as individuals. Aeon; 2023.
- Ganora, L. Herbal Constituents: Foundations of Phytochemistry. Herbalchem Press; 2009.
- Fu, PP, Xia Q, Lin G, Chou MW. Pyrrolizidine alkaloids—genotoxicity, metabolism enzymes, metabolic activation, and mechanisms. Drug metabolism reviews. 2004;36(1):1-55. https://doi.org/10.1081/DMR-120028426
- Avila C, Breakspear I, Hawrelak J, Salmond S, Evans S. A systematic review and quality assessment of case reports of adverse events for borage (Borago officinalis), coltsfoot (Tussilago farfara) and comfrey (Symphytum officinale). Fitoterapia. 2020;142:104519.https://doi.org/10.1016/j.fitote.2020.104519
- Culpeper, N. Culpepers’ Complete Herbal: a book of natural remedies for ancient ills [1653]. Wordworth Reference; 1995.
- Woodville, W. Medical Botany: 1790-1794. Tussilago farfara, Coltsfoot. Reprinted on Henritttas Herbpages. Accessed September 8, 2024. https://www.henriettes-herb.com/eclectic/woodville/tussilago.html
- Grieve M, Leyel CF, Marshall M. A Modern Herbal. the Medicinal, Culinary, Cosmetic and Economic Properties, Cultivation and Folk-Lore of Herbs, Grasses, Fungi, Shrubs & Trees with All Their Modern Scientific Uses [1931]. Dover Publications; 1992.
- Felter H. W, Lloyd J. U. Kings American Dispensary; 18th Edit; 1898. Reprinted on Henritttas Herbpages. Accessed September 8, 2024. https://www.henriettes-herb.com/eclectic/kings/tussilago.html
- Blumenthal M, Busse WR. White Mustard Seed. In: The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council; 1999. Accessed September 17, 2024. https://www.herbalgram.org/resources/commission-e-monographs/monograph-approved-herbs/coltsfoot-leaf/
- Hoffman D. Medicinal Herbalism, The Science and Practice of Herbal Medicine. Healing Arts Press; 2003.
- Heinrich, M., Barnes, J., Prieto-Garcia, J., Gibbons, S. and Williamson, E.M. Fundamentals of Pharmacognosy and Phytotherapy. Third Edition. Elsevier Health Sciences; 2018.
- Fisher C. Materia Medica of Western Herbs. Aeon Books; 2018.
- Fischer-Rizzi, S. Complete Earth Medicine Handbook. Sterling Publishing; 1996.
- Cheon, H. J., Nam, S. H., & Kim, J. K. Tussilagone, a major active component in Tussilago farfara, ameliorates inflammatory responses in dextran sulphate sodium-induced murine colitis. Chemico-biological interactions. 2018;294, 74–80. https://doi.org/10.1016/j.cbi.2018.08.022
- McIntyre A, Boudin M. Dispensing with Tradition: A Practitioner’s Guide to Using Indian and Western Herbs the Ayurvedic Way. Anne McIntyre & Michelle Boudin; 2012.
- Fu, JX. (1989) Measurement of MEFV in 66 cases of asthma in the convalescent stage and after treatment with Chinese herbs. Chinese Journal of Modern Developments in Traditional Medicine. 1989;9 (11):658-9.
- Brinker, FJ. Herbal Contraindications & Drug Interactions: Plus Herbal Adjuncts with Medicines. Eclectic Medical Publications, 2010.
- Burton-Seal, J. and Seal, M. The Herbalist Bible: John Parkinson’s Lost Classic Rediscovered. Merline Unwin Books; 2014.
- Thomsen M. The Phytotherapy Desk Reference: 6th Edition. 6th ed. Aeon Books; 2022.
- Natural Medicines Professional Database Therapeutic Research Centre. Coltsfoot Professional Monograph. Published Sept 13, 2023. Accessed September 17, 2024. https://naturalmedicines.therapeuticresearch.com/
- Killick, HJ. Tussilago farfara L. in BSBI Online Plant Atlas. Published 2020, eds Stroh, PA, Humphrey, TA, Burkmar, RJ, Pescott, OL, Roy, DB & Walker, KJ. Accessed September 8, 2024. https://plantatlas2020.org/atlas/2cd4p9h.258
- Royal Horticultural Society. Tussilago farfara – Coltsfoot. Accessed September 7, 2024. https://www.rhs.org.uk/plants/18563/tussilago-farfara/details
- Blamey M, Fitter R, Fitter AH. Wild Flowers of Britain and Ireland: 2Nd Edition. A & C Black; 2013.
- Royal Botanical Gardens Kew. Tussilago farfara L. Plants of the Word Online (POWO). Accessed September 7, 2024. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:256904-1
- Khela, S. Tussilago farfara (Europe assessment). The International Union for Conservation of Nature (IUCN) Red List of Threatened Species 2012. November 6, 2012. Accessed September 7, 2024. https://www.iucnredlist.org/species/202995/2758465
- Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Accessed September 7, 2024. https://checklist.cites.org/#/en
- United Plant Savers. UpS list of herbs & analogs. Published May 14, 2021. Accessed September 8, 2024. https://unitedplantsavers.org/ups-list-of-herbs-analogs/
- NatureServe explorer 2.0. Natureserve.org. Tussilago farfara. Accessed September 7, 2024. https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.147257/Tussilago_farfara
- Cheffings C, Farrell L, Dines T et al. The Vascular Plant Red Data List for Great Britain. Species Status No. 7. JNCC. Published 2005. Accessed September 7, 2024. https://hub.jncc.gov.uk/assets/cc1e96f8-b105-4dd0-bd87-4a4f60449907