Tussilago farfara, commonly known as coltsfoot,:770 is a plant in the groundsel tribe in the daisy family Asteraceae, native to Europe and parts of western and central Asia. The name "tussilago" is derived from the Latin tussis, meaning cough, and ago, meaning to cast or to act on. It has had uses in traditional medicine, but the discovery of toxic pyrrolizidine alkaloids in the plant has resulted in liver health concerns.
Tussilago farfara is the only accepted species in the genus Tussilago, although more than two dozen other species have at one time or another been considered part of this group. Most of them are now regarded as members of other genera (Chaptalia, Chevreulia, Farfugium, Homogyne, Leibnitzia, Petasites, Senecio).
Coltsfoot is a perennial herbaceous plant that spreads by seeds and rhizomes. Tussilago is often found in colonies of dozens of plants. The flowers, which superficially resemble dandelions, bear scale-leaves on the long stems in early spring. The leaves of coltsfoot, which appear after the flowers have set seed, wither and die in the early summer. The flower heads are of yellow florets with an outer row of bracts. The plant is typically 10–30 cm in height. The leaves have angular teeth on their margins.
Coltsfoot is widespread across Europe, Asia, and North Africa, from Svalbard to Morocco to China and the Russian Far East. It is also a common plant in North and South America where it has been introduced, most likely by settlers as a medicinal item. The plant is often found in waste and disturbed places and along roadsides and paths. In some areas it is considered an invasive species.
The common name comes from the leaf's supposed resemblance to a colt's foot. Other common names include tash plant, ass's foot, bull's foot, coughwort (Old English), farfara, foal's foot, foalswort and horse foot. Sometimes it is confused with Petasites frigidus, or western coltsfoot.
Coltsfoot has been used in herbal medicine and has been consumed as a food product with some confectionery products, such as Coltsfoot Rock. Tussilago farfara leaves have been used in the traditional Austrian medicine internally (as tea or syrup) or externally (directly applied) for treatment of disorders of the respiratory tract, skin, locomotor system, viral infections, flu, colds, fever, rheumatism and gout. An extract of the fresh leaves has also been used make cough drops and hard candy.
Tussilago farfara contains tumorigenic pyrrolizidine alkaloids. Senecionine and senkirkine, present in coltsfoot, have the highest mutagenetic activity of any pyrrolozidine alkaloid, tested using Drosophila melanogaster to produce a comparative genotoxicity test.
Two cases of supposed liver damage (and death) due to coltsfoot tea have been shown to actually be the result of mistaken identity. In one, coltsfoot tea causing severe liver problems in an infant was actually the result of Adenostyles alliariae (Alpendost). In another case, an infant developed liver disease and died because the mother drank tea originally believed to contain coltsfoot during her pregnancy, but which was later shown to be Petasites hybridus (butterbur) or a similar species. In one 27-year-old white male, ingesting a multicomponent herbal supplement that included coltsfoot may have caused him to develop non-lethal deep vein thrombosis and pulmonary embolism.
In response the German government banned the sale of coltsfoot. Clonal plants of coltsfoot free of pyrrolizidine alkaloids were then developed in Austria and Germany. This has resulted in the development of the registered variety Tussilago farfara 'Wien' which has no detectable levels of these alkaloids.
- Flann, C (ed) 2009+ Global Compositae Checklist Archived 2014-11-06 at Archive.today
- Stace, C. A. (2010). New Flora of the British Isles (Third ed.). Cambridge, U.K.: Cambridge University Press. ISBN 9780521707725.
- "Tussilago farfara". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 12 December 2015.
- Capasso, Francesco (2011). "Capitolo M12: Droghe obsolete e/o poco studiate". Farmacognosia: Botanica, chimica e farmacologia delle piante medicinali (in Italian) (Seconda edizione ed.). Springer Milan. p. 428. doi:10.1007/978-88-470-1652-1_30. ISBN 978-88-470-1652-1.
Tussilago, dal latino tussis = tosse e ago = scaccio.
- Booth, David (1835). An analytical dictionary of the English language. James Cochrane and Co. p. 312.
Tussilago, from the Latin tussis, a cough, and ago, to act upon, to cure; from its reputed virtues.
- Theodore M. Barkley (2006). "Tussilago Linnaeus, Sp. Pl. 2: 865. 1753; Gen. Pl. ed. 5, 372. 1754". Magnoliophyta: Asteridae, Part 7: Asteraceae, Part 2. Flora of North America. 20. Oxford University Press. p. 635. ISBN 9780195305647.
- Parnell, J. and Curtis, T. 2012 Webb's An Irish Flora. Cork University PressISBN 978-185918-4783
- Flora of China Vol. 20-21 Page 461 款冬 kuan dong Tussilago farfara Linnaeus, Sp. Pl. 2: 865. 1753.
- Altervista Flora Italiana, genere Tussilago includes photos and distribution maps
- Niering, William A.; Olmstead, Nancy C. (1985) . The Audubon Society Field Guide to North American Wildflowers, Eastern Region. Knopf. p. 410. ISBN 0-394-50432-1.
- Coulombe Jr., Roger A. (2003). "Pyrrolizidine Alkaloids in Foods". In Taylor, Steve L. (ed.). Advances in Food and Nutrition Research. 45. Academic Press. p. 76. ISBN 0-12-016445-0.
- First Foot: The Medieval Garden Enclosed. The Metropolitan Museum of Art, New York
- Joannes de Vigo. Works of Chirurgery, 1543.
- Thomas Cooper, Thesaurus Linguae Romanae et Britannicae (1584).
- Sylvia Vogl, Paolo Picker, Judit Mihaly-Bison, Nanang Fakhrudin, Atanas G. Atanasov, Elke H. Heiss, Christoph Wawrosch, Gottfried Reznicek, Verena M. Dirsch, Johannes Saukel & Brigitte Koppa (2013). "Ethnopharmacological in vitro studies on Austria's folk medicine – an unexplored lore in vitro anti-inflammatory activities of 71 Austrian traditional herbal drugs". Journal of Ethnopharmacology. 149 (3): 750–771. doi:10.1016/j.jep.2013.06.007. PMC 3791396. PMID 23770053.CS1 maint: multiple names: authors list (link)
- Fu, P.P., Yang, Y.C., Xia, Q., Chou, M.C., Cui, Y.Y., Lin G., "Pyrrolizidine alkaloids-tumorigenic components in Chinese herbal medicines and dietary supplements", Journal of Food and Drug Analysis, Vol. 10, No. 4, 2002, pp. 198-211 
- Röder, E., "Medicinal plants in Europe containing pyrrolizidine alkaloids", Pharmazie, 1995, pp83-98. Reprinted on Henriette's Herbal website.
- Frei, H.J., Luethy, J., Brauchli, L., Zweifel, U., Wuergler, F.E., & Schlatter, C., Chem. Biol. Interact., 83: 1, 1992
- Sperl, W., Stuppner, H., Gassner, I.; "Reversible hepatic veno-occlusive disease in an infant after consumption of pyrrolizidine-containing herbal tea." Eur. J. Pediatr. 1995;154:112–6.
- Roulet, M., Laurini, R., Rivier, L., Calame, A.; "Hepatic veno-occlusive disease in newborn infant of a woman drinking herbal tea." J Pediatrics. 1988;112:433–6.
- Frohne D, Pfänder HJ. Poisonous Plants: A Handbook for Doctors, Pharmacists, Toxicologists, Biologists and Veterinarians. Timber Press, 2005.
- Freshour JE, Odle B, Rikhye S, Stewart DW. Coltsfoot as a potential cause of deep vein thrombosis and pulmonary embolism in a patient also consuming kava and blue vervain. J Diet Suppl. 2012;9(3):149-54. doi: 10.3109/19390211.2012.708391.
- Wawrosch, Ch.; Kopp, B.; Wiederfield, H.; "Permanent monitoring of pyrrolizidine alkaloid content in micropropagated Tussilago farfara L. : A tool to fulfill statutory demands for the quality of coltsfoot in Austria and Germany", Acta horticulturae, 2000, no. 530, pp469-472 
- Wawrosh C.,"In Vitro Cultivation of Medicinal Plants" cited in Yaniv Z. and Bachrach U., Eds "Handbook of Medicinal Plants", The Hawthorne Medical Press NY Lond. 2005
- R. Schubert & G. Wagner: Botanisches Wörterbuch Ulmer, Stuttgart 1993, ISBN 3-8252-1476-1 (in German)
- H. Haeupler & Th. Muer: Bildatlas der Farn- und Blütenpflanzen Deutschlands Ulmer Verlag, Stuttgart, 2000. ISBN 3-8001-3364-4. (in German)
- Gerhard Madaus: Lehrbuch der biologischen Heilmittel Bd 1. Heilpflanzen. G. Thieme, Leipzig 1938, Olms, Hildesheim 1979. ISBN 3-487-05890-1 (in German)
- Guide des plantes sauvages comestibles et toxiques, les guides du naturaliste, François Couplan et Eva Stinner ISBN 2-603-00952-4 (in French)
- Кирпичников М. Э. Семейство сложноцветные, или астровые (Asteraceae, или Compositae) // Жизнь растений. В 6-ти т. / Под ред. А. Л. Тахтаджяна. — М.: Просвещение, 1981. — Т. 5. Ч. 2. Цветковые растения. — С. 462—476. — 300000 экз. (in Russian)