Tussilago farfara, commonly known as coltsfoot,<ref name=Stace>Template:Cite book</ref>Template:Rp<ref>Template:PLANTS</ref> 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.<ref>Template:Cite book</ref><ref>Template:Cite book</ref> 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).<ref name=u>Flann, C (ed) 2009+ Global Compositae Checklist Template:Webarchive</ref>
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, open on leafless stems in early spring before the leaves appear. The leaves, which resemble a colt's foot in outline appear after the flowers have set seed and wither and die in the early summer. The plant is typically 10–30 cm in height. The leaves have angular teeth on their margins.<ref>Template:Cite book</ref>
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 America 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.<ref name=u/><ref>Flora of China Vol. 20-21 Page 461 款冬 kuan dong Tussilago farfara Linnaeus, Sp. Pl. 2: 865. 1753. </ref><ref>Altervista Flora Italiana, genere Tussilago includes photos and distribution maps</ref>
Other common names include tash plant, ass's foot, bull's foot, coughwort (Old English),<ref>Template:Cite book</ref> farfara, foal's foot, foalswort and horse foot. Sometimes it is confused with Petasites frigidus, or western coltsfoot.
It has been called bechion<ref name="blog.metmuseum.org">First Foot: The Medieval Garden Enclosed. The Metropolitan Museum of Art, New York</ref> bechichie or bechie, from the Ancient Greek word for "cough".<ref>Joannes de Vigo. Works of Chirurgery, 1543.</ref> Also ungula caballina ("horse hoof"), pes pulli ("foal's foot"),<ref name="blog.metmuseum.org"/> and chamæleuce.<ref>Thomas Cooper, Thesaurus Linguae Romanae et Britannicae (1584).</ref>
Coltsfoot has been used in herbal medicine<ref name="blog.metmuseum.org"/> 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.<ref>Template:Cite journal</ref>
Tussilago farfara contains tumorigenic pyrrolizidine alkaloids.<ref name=Fu1>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 </ref> 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.<ref>Röder, E., "Medicinal plants in Europe containing pyrrolizidine alkaloids", Pharmazie, 1995, pp83-98. Reprinted on Henriette's Herbal website.</ref><ref>Frei, H.J., Luethy, J., Brauchli, L., Zweifel, U., Wuergler, F.E., & Schlatter, C., Chem. Biol. Interact., 83: 1, 1992</ref> There are documented cases of coltsfoot tea causing severe liver problems in an infant, and in another case, an infant developed liver disease and died because the mother drank tea containing coltsfoot during her pregnancy.<ref>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.</ref><ref>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.</ref> 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.<ref>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 </ref> This has resulted in the development of the registered variety Tussilago farfara 'Wien' which has no detectable levels of these alkaloids.<ref>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</ref>
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