Echinacea#Medicinal effects

Image:Echinacea 3.jpgImage:Yellow Coneflower Echinacea paradoxa Closeup Bee 3008px.jpg)]]

Image:Bee pollinating a flower at the National Zoo.jpg head]]

File:Fasciation on an Echinacea purpurea.jpg on an Echinacea purpurea]]

Echinacea species are herbaceous, drought-tolerant perennial plants growing up to {{convert|140|cm|ftin|abbr=on}} in height. They grow from taproots, except E. purpurea, which grows from a short caudex with fibrous roots. They have erect stems that in most species are unbranched. Both the basal and cauline (stem) leaves are arranged alternately. The leaves are normally hairy with a rough texture, having uniseriate trichomes (1–4 rings of cells), but sometimes they lack hairs. The basal leaves and the lower stem leaves have petioles, and as the leaves progress up the stem the petioles often decrease in length. The leaf blades in different species may have one, three, or five nerves. Some species have linear to lanceolate leaves, and others have elliptic- to ovate-shaped leaves; often the leaves decrease in size as they progress up the stems. Leaf bases gradually increase in width away from the petioles or the bases are rounded to heart shaped. Most species have leaf margins that are entire, but sometimes they are dentate or serrate.

The flowers are collected together into single rounded heads at the ends of long peduncles. The inflorescences have crateriform to hemispheric shaped involucres which are {{convert|12|-|40|mm|in|abbr=on}} wide. The phyllaries, or bracts below the flower head, are persistent and number 15–50. The phyllaries are produced in a 2–4 series. The receptacles are hemispheric to conic. The paleae (chaffs on the receptacles of many Asteraceae) have orange to reddish purple ends, and are longer than the disc corollas. The paleae bases partially surrounding the cypselae, and are keeled with the apices abruptly constricted to awn-like tips. The ray florets number 8–21 and the corollas are dark purple to pale pink, white, or yellow. The tubes of the corolla are hairless or sparsely hairy, and the laminae are spreading, reflexed, or drooping in habit and linear to elliptic or obovate in shape. The abaxial faces of the laminae are glabrous or moderately hairy. The flower heads have typically 200–300 fertile, bisexual disc florets but some have more. The corollas are pinkish, greenish, reddish-purple or yellow and have tubes shorter than the throats. The pollen is normally yellow in most species, but usually white in E. pallida. The three or four-angled fruits (cypselae), are tan or bicolored with a dark brown band distally. The pappi are persistent and variously crown-shaped with 0 to 4 or more prominent teeth. x = 11.{{sfn|Urbatsch et al|2006}}

Like all members of the sunflower family, the flowering structure is a composite inflorescence, with rose-colored (rarely yellow or white) florets arranged in a prominent, somewhat cone-shaped head – "cone-shaped" because the petals of the outer ray florets tend to point downward (are reflexed) once the flower head opens, thus forming a cone. Plants are generally long lived, with distinctive flowers. The common name "coneflower" comes from the characteristic center "cone" at the center of the flower head.

The first Echinacea species were named by European explorers after seeing them in the forests of southeastern North America during the 18th century.{{sfn|Binns et al|2004}} The genus Echinacea was then formally described by Linnaeus in 1753, and this specimen as one of five species of Rudbeckia, Rudbeckia purpurea.{{sfn|Linnaeus|1753}}{{sfn|Binns et al|2001}} Conrad Moench subsequently reclassified it in 1794 as the separate but related genus, Echinacea, with the single species Echinacea purpurea,{{sfn|Moench|1794}}{{sfn|Kindscher|Wittenberg|2006|p=9}} so that the botanical authority is given as (L.) Moench.{{sfn|Tropicos|2021}} In 1818, Nuttall, using the original name, described a variety of Rudbeckia purpurea, which he named Rudbeckia purpurea var serotina.{{sfn|Nuttall|1818|p=2:178}} In 1836, De Candolle elevated this variety to a species in its own right, as Echinacea serotina (Nutt.) DC, by which time four species of the genus Echinacea were recognised.{{sfn|de Candolle|1824–1873|p=5: 554}}{{sfn|Binns et al|2004}}

Historically, there has been much confusion over the taxonomic treatment of the genus, largely due to the ease with which the taxa hybridize with introgression where species ranges overlap, and high morphological variation.{{sfn|McGregor|1968}}{{sfn|Kindscher|Wittenberg|2016|p=38}} Furthermore it was discovered that the type specimen for Echinacea purpurea (L) Moench was not the one originally described by Linnaeus, but rather that described by De Candolle as Echinacea serotina (Nutt.) DC.{{sfn|Binns et al|2004}}

Many taxonomic treatments of the genus Echinacea have recorded varying numbers of subordinate taxa, ranging between 2 and 11.{{sfn|Binns et al|2004}} One of the most widely adopted schemes was that of McGregor (1968),{{sfn|McGregor|1968}} which included nine species, of which two, E. angustifolia DC and E. paradoxa (Norton) Britton, were further divided into two varietals.{{sfn|Kindscher|Wittenberg|2006|p=9}} Treatments that include ten species, differ by the addition of E. serotina (Nutt.) DC.{{sfn|Flagel et al|2008}} Alternative classification include with four species and eight subspecies, and two subgenera with four species, has been proposed, based on morphology alone, but has proved controversial.{{sfn|Kindscher|Wittenberg|2016|p=38}} This recognised subgenus Echinacea, with the single species E. purpurea, and subgenus Pallida, with three species, E. atrorubens, E. laevigata and E. pallida. In this scheme, other taxa are reduced to variety rank, e.g. E. atrorubens var. neglecta.{{sfn|Binns et al|2001}}{{sfn|Binns et al|2002}} Subsequently, McGregor's classification was preserved in the Flora of North America (2006).{{sfn|Urbatsch et al|2006}}

DNA analysis has been applied to determine the number of Echinacea species, allowing clear distinctions among species based on chemical differences in root metabolites. The research concluded that of the 40 genetically diverse populations of Echinacea studied, there were nine to ten distinct species.{{sfn|Perry|2010}}

Plants of the World Online gives nine accepted species,{{sfn|POWO|2021}} and World Flora Online gives ten:{{sfn|WFO|2021}}

• Echinacea angustifolia – Narrow-leaf coneflower
• Echinacea atrorubens – Topeka purple coneflower
• Echinacea laevigata – Smooth coneflower, smooth purple coneflower
• Echinacea pallida – Pale purple coneflower
• Echinacea paradoxa – Yellow coneflower, Bush's purple coneflower
• Echinacea purpurea – Purple coneflower, eastern purple coneflower
• Echinacea sanguinea – Sanguine purple coneflower
• Echinacea serotina – Narrow-leaved purple coneflower
• Echinacea simulata – Wavyleaf purple coneflower
• Echinacea tennesseensis – Tennessee coneflower

These two databases differ in their treatment of E. serotina (Nutt.) DC. , the former considering this as a synonym of E. purpurea and the latter as a distinct species.

• Rudbeckia
• Brauneria (1790){{sfn|Kindscher|Wittenberg|2016|p=38}}

Moench named the genus Echinacea, from the Greek word {{lang|grc|ἐχῖνος}} ({{transliteration|grc|ekhinos}}) for hedgehog or sea-urchin, in recognition that in the seed stage, the cone has spiny projections.{{sfn|Kindscher|Wittenberg|2006|p=9}}{{sfn|Plowden|1972|loc=[https://drugs.org/details/manualofplantnam0000plow/page/47 p. 7]}}

Echinacea is restricted to North America, east of the Rocky Mountains, and in the Atlantic drainage area, predominantly the Great Plains and central United States and adjacent areas of Canada.{{sfn|Binns et al|2002}}{{sfn|Binns et al|2004}}{{sfn|Kindscher|2021}} The genus range is from Saskatchewan in the north to almost the Gulf of Mexico in Louisiana and Texas in the south, and from the Ohio oak savannas, glades of Tennessee and the Carolinas in the east, to the Rocky Mountain foothills in the west.{{sfn|Flagel et al|2008}}

Natural populations of Echinacea are threatened by over-harvesting of wild specimens for the herbal product trade and modification of their habitats by humans.{{sfn|Kindscher|2021}} Major reductions in the size of populations of E. laevigata and E. tennesseensis have led to their classification as endangered species.{{sfn|Binns et al|2002}}{{sfn|Kindscher|2006}} E. tennesseensis had recovered sufficiently by 2011 that it was removed from the list.{{sfn|Fish and Wildlife Service|2011}}

Many species of Echinacea are cultivated for commercial use,{{sfn|Binns et al|2002}} while others, notably E. purpurea, E. angustifolia, and E. pallida, are grown as ornamental plants in gardens.{{sfn|McCoy et al|2005}} Many cultivars exist, and many of them are asexually propagated to keep them true to type.

Echinacea has long been used as a traditional medicine.{{sfn|Binns et al|2002}}

Echinacea angustifolia was widely used by the North American Indigenous peoples as folk medicine, with archaeological evidence dating back to the 18th century. Traditional use included external application (insect bites, burns, wounds), chewing of roots (throat and tooth infections) and internal use (cough, pain, snake bites, stomach cramps).{{sfn|Hostettmann |2003}}{{sfn|Kindscher|2007|p=156}} Some Plains tribes used Echinacea for cold symptoms. The Kiowa used it for coughs and sore throats, the Cheyenne for sore throats, the Pawnee for headaches, and many tribes, including the Lakota, used it as a pain medication.{{sfn|Moerman|1998|p=205}} Early European settlers noticed this and began to develop their own uses. According to Wallace Sampson, its modern use for the common cold began when a Swiss herbal supplement maker was told that Echinacea was used for cold prevention by Native American tribes who lived in the area of South Dakota.{{sfn|Chang|2007}} The first preparation was Meyers Blood Purifier ({{Circa|1880}}), which was promoted for neuralgia, rattlesnake bites and rheumatism. By the start of the 20th century it was the most common herbal remedy in America.{{citation needed|date=November 2021}} Commercial cultivation began in Germany in the late 1930s, and in Switzerland in 1950, by A. Vogel. Soon chemists and pharmacologists began the task of identifying potentially active ingredients and their properties. These included alyklamides, cichoric acid, echinacoside, ketoalkenes and polysaccharides. Extracts appeared to exhibit immunostimulant properties and were mainly promoted for the prevention and treatment of colds, influenza and sepsis. Despite many different preparations and hundreds of publications, no exact identification of a truly active ingredient has been identified.{{sfn|Hostettmann |2003}}

A 2014 meta-analysis found weak evidence for Echinacea in treating, preventing, or reducing the severity of the common cold.{{sfn|Karsch-Volk et al|2014}} A 2015 meta-analysis found tentative evidence that use of Echinacea extracts reduced the risk of repeated respiratory infections.{{sfn|Schapowal et al|2015}}

When taken by mouth, Echinacea does not usually cause side effects,{{sfn|NCCIH|2020}} but may have undesirable interactions with various drugs prescribed for diseases, such as heart disease, bleeding, and autoimmune diseases, such as rheumatoid arthritis, lupus, or psoriasis.{{sfn|Natural Standard Research Collaboration|2013}}{{sfn|Drugsite|2021}} Although there are no specific case reports of drug interactions with Echinacea,{{sfn|Izzo|Ernst|2009}} safety about taking Echinacea supplements is not well understood, with possibilities that it may cause side effects, such as nausea, stomach upset or diarrhea, and that it may have adverse reactions with other medications.{{sfn|Natural Standard Research Collaboration|2013}} One of the most extensive and systematic studies to review the safety of Echinacea products concluded that overall, "adverse events are rare, mild and reversible," with the most common symptoms being "gastrointestinal and skin-related."{{sfn|Huntley et al|2005}} Such side effects include nausea, abdominal pain, diarrhea, itch, and rash.{{sfn|Drugsite|2021}} Echinacea has also been linked to allergic reactions, including asthma, shortness of breath, and one case of anaphylaxis.{{sfn|Huntley et al|2005}}{{sfn|Mullins|1998}}{{sfn|Ang-Lee et al|2001}} Muscle and joint pain has been associated with Echinacea, but it may have been caused by cold or flu symptoms for which the Echinacea products were administered.{{sfn|Huntley et al|2005}} There are isolated case reports of rare and idiosyncratic reactions including thrombocytopenic purpura, leucopenia, hepatitis, kidney failure, and atrial fibrillation, although it is not clear that these were due to Echinacea itself.{{sfn|Natural Standard Research Collaboration|2013}} Up to 58 drugs or supplements may interact with Echinacea.{{sfn|Drugsite|2021}}

As a matter of manufacturing safety, one investigation by an independent-consumer testing laboratory found that five of eleven selected retail Echinacea products failed quality testing. Four of the failing products contained levels of phenols below the potency level stated on the labels. One failing product was contaminated with lead.{{sfn|Cooperman|2021}}

The European Herbal Medicinal Products Committee (HMPC) and the UK Herbal Medicines Advisory Committee (HMAC) recommended against the use of Echinacea-containing products in children under the age of 12. Manufacturers re-labelled all oral Echinacea products that had product licenses for children with a warning that they should not be given to children under 12 as a precautionary measure.{{sfn|MHRA|2014}}

Although research has not found increased risk of birth defects associated with use of Echinacea during the first trimester, it is recommended that pregnant women should avoid Echinacea products until stronger safety supporting evidence becomes available.{{sfn|Natural Standard Research Collaboration|2013}}

It is recommended that women breastfeeding should use caution with Echinacea products due to insufficient safety information available.{{sfn|Natural Standard Research Collaboration|2013}}

The U.S. Food and Drug Administration recommends precaution about using dietary supplements because some products may not be risk free under certain circumstances or may interact with prescription and over-the-counter medicines.{{sfn|FDA|2017}}

As with any herbal preparation, individual doses of Echinacea may vary significantly in chemical composition.{{sfn|NCCIH|2020}} Inconsistent process control in manufactured echinacea products may involve poor inter- and intra-batch homogeneity, species or plant part differences, variable extraction methods, and contamination or adulteration with other products, leading to potential for substantial product variability.{{sfn|Karsch-Volk et al|2014}}{{sfn|Cooperman|2021}}

Echinacea products vary widely in composition.{{sfn|NCCIH|2020a}} They contain different species (E. purpurea, E. angustifolia, E. pallida), different plant segments (roots, flowers, extracts), different preparations (extracts and expressed juice), and different chemical compositions which complicate understanding of a potential effect.{{sfn|Barnes et al|2005}}{{sfn|Hart|Dey|2009}}

Well-controlled clinical trials{{sfn|Turner et al|2005}} are limited and low in quality, with little scientific evidence that Echinacea supplement products are useful for treating any disease.{{sfn|Drugsite|2021}}{{sfn|Hart|Dey|2009}}{{sfn|Karsch-Volk et al|2014}}

According to Cancer Research UK, "There is no scientific evidence to show that echinacea can help treat, prevent or cure cancer in any way. Some therapists have claimed that echinacea can help relieve side effects from cancer treatments such as chemotherapy and radiotherapy, but this has not been proven either."{{sfn|Cancer Research UK|2019}}

Although there are multiple scientific reviews and meta-analyses{{sfn|Shah et al |2007}} published on the supposed immunological effects of Echinacea, there is significant variability of products used among studies, leading to low-quality or no evidence for efficacy and safety, leading to considerable controversy.{{sfn|Chang|2007}} Consequently, regulatory authorities, such as the United States Food and Drug Administration, have not approved Echinacea products as safe and effective for any health or therapeutic purpose.{{sfn|NCCIH|2020}}{{sfn|Drugsite|2021}}{{sfn|Hart|Dey|2009}}

• List of ineffective cancer treatments

{{Reflist|20em}}

{{Refbegin|30em}}

• {{cite web|last=European Union|author-link=European Union|title=European Union herbal monograph on Echinacea purpurea (L.) Moench, herba recens|url=http://www.ema.europa.eu/docs/en_GB/document_library/Herbal_-_Community_herbal_monograph/2015/04/WC500185437.pdf|publisher=Committee on Herbal Medicinal Products, European Medicines Agency|date=24 November 2015|access-date=16 March 2018|archive-date=19 June 2018|archive-url=https://web.archive.org/web/20180619002157/http://www.ema.europa.eu/docs/en_GB/document_library/Herbal_-_Community_herbal_monograph/2015/04/WC500185437.pdf|url-status=dead}}
• {{cite book|editor-last1=Kindscher|editor-first1=Kelly|title=The Conservation Status of Echinacea Species|url=http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fsm91_054353.pdf|publisher=USDA|date=30 September 2006}}
• {{cite book |editor1-last=Kindscher |editor1-first=Kelly |title=Echinacea: Herbal Medicine with a Wild History |date=2016 |publisher=Springer Nature |isbn=978-3-319-18155-4 |url=https://books.google.com/books?id=pQBkDAAAQBAJ }}{{link note|note=additional excerpts [https://www.springer.com/gp/book/9783319181554 here]}}
• {{cite book |last=McKeown |first=K A |editor-last1=Janick |editor-first1=Jules |title=Perspectives on New Crops and New Uses |date=1999 |publisher=ASHS Press |isbn=978-0-9615027-0-6 |url=https://books.google.com/books?id=NR1IAAAAYAAJ |chapter=A Review of the Taxonomy of the Genus Echinacea |pages=482–489 |chapter-url=https://hort.purdue.edu/newcrop/proceedings1999/v4-482.html }}
• {{cite book |editor-last1=Miller |editor-first1=Sandra Carol |editor-last2=Yu |editor-first2=He-ci |title=Echinacea: The genus Echinacea |series=Medicinal and Aromatic Plants - Industrial Profiles |date=2004 |publisher=CRC Press |isbn=978-0-203-02269-6 |url=https://books.google.com/books?id=WT48zTwLa9AC }}
• {{cite book |last1=Moerman |first1=Daniel E. |title=Native American Ethnobotany |date=1998 |publisher=Timber Press |isbn=978-0-88192-453-4 |url=https://books.google.com/books?id=UXaQat5icHUC }}
• {{cite book|last=Mowrey|first=Daniel|name-list-style=vanc|title=Echinacea|publisher=McGraw-Hill Professional|year=1998|isbn=978-0-87983-610-8|url=https://books.google.com/books?id=WlRXleQhLeQC}}
• {{cite book |last1=Plowden |first1=C. Chicheley |title=A Manual of Plant Names |date=1972 |edition=3rd |origyear=1968 |publisher=Allen & Unwin |isbn=978-0-04-580007-0 |url=https://books.google.com/books?id=N6sgAQAAIAAJ }}{{link note|note=Available [https://archive.org/details/manualofplantnam0000plow/page/n3/mode/2up here] at Internet Archive}}

;Historical sources

• {{cite book |last1=de Candolle |first1=A. P. |author-link=Augustin Pyramus de Candolle |title=Prodromus systematis naturalis regni vegetabilis, sive, Enumeratio contracta ordinum generum specierumque plantarum huc usque cognitarium, juxta methodi naturalis, normas digesta 17 vols. |date=1824–1873 |publisher=Treuttel et Würtz |location=Paris |url=https://www.biodiversitylibrary.org/bibliography/286#/summary }}
• {{cite book|last=Linnaeus|first=Carl|author-link=Linnaeus|title=Species Plantarum: exhibentes plantas rite cognitas, ad genera relatas, cum differentiis specificis, nominibus trivialibus, synonymis selectis, locis natalibus, secundum systema sexuale digestas. 2 vols.|url=https://www.biodiversitylibrary.org/bibliography/669#/summary|year=1753|volume=2|chapter=Rudbeckia|chapter-url=https://www.biodiversitylibrary.org/item/13830#page/349/mode/1up|page=907|publisher=Impensis Laurentii Salvii|location=Stockholm}}, see also Species Plantarum
• {{cite book |last1=Moench |first1=Conrad |author-link=Conrad Moench |title=Methodus plantas horti botanici et agri Marburgensis: a staminum situ describendi |date=1794 |publisher=Marburgi cattorum: in officina nova libraria academiae |location=Marburg |url=https://www.biodiversitylibrary.org/bibliography/304 |language=latin |chapter=Echinacea |page=591 |chapter-url=https://www.biodiversitylibrary.org/page/449222#page/224/mode/1up }}
• {{cite book |last1=Nuttall |first1=Thomas |author-link=Thomas Nuttall |title=The Genera of North American Plants: And a Catalogue of the Species, to the Year 1817. 2 vols. |date=1818 |publisher=Nuttall |location=Philadelphia |url=https://books.google.com/books?id=WYZIAAAAYAAJ |volume=1 |isbn=9780608408859 }}{{link note|note=[https://books.google.com/books?id=Pk8-AAAAcAAJ Volume 2], both volumes also available [https://www.biodiversitylibrary.org/bibliography/290 here] at BHL}}

• {{cite encyclopedia |editor1-link=David J. Wishart |editor-last1=Wishart |editor-first1=David J. |title=Encyclopedia of the Great Plains Indians |date=2007 |publisher=University of Nebraska Press |isbn=978-0-8032-9862-0 |url=https://books.google.com/books?id=646oX4hA8EkC |last=Kindscher |first=Kelly |chapter=Plant Lore |page=166 }}{{link note|note=Excerpted and expanded from {{cite encyclopedia |url=https://books.google.com/books?id=rtRFyFO4hpEC |title=Encyclopedia of the Great Plains |date=2004 |isbn=978-0-8032-4787-1 |page=309 |last1=Wishart |first1=David J. |publisher=U of Nebraska Press }}, also searchable at Internet Archive, [https://archive.org/details/encyclopediagrea00wish_849/page/n166 here]}}
• {{cite book |last1=Kindscher |first1=Kelly |last2=Wittenberg |first2=Rebecca |title=The naming and classification of Echinacea species |date=2006|pages=8–31}}, in {{harvtxt|Kindscher|2006}}
• {{cite book |last1=Kindscher |first1=Kelly |last2=Wittenberg |first2=Rebecca |title=The naming and classification of Echinacea species |date=2016|pages=37–45}}, in {{harvtxt|Kindscher|2016}}
• {{cite book |last1=Binns |first1=S. E. |last2=Arnason |first2=J. T. |last3=Baum |first3=B. R. |title=Taxonomic history and revision of the genus Echinacea |date=2004 |pages=3–11|ref={{harvid|Binns et al|2004}}}}, in {{harvtxt|Miller|Yu|2004}}
• {{cite book|last=Panero|first=J L|editor-last=Kadereit|editor-first=Joachim W.|editor2-last=Jeffrey|editor2-first=Charles|editor3-last=Kubitzki|editor3-first=Klaus|editor-link3=Klaus Kubitzki|title=The families and genera of vascular plants v. 8 Flowering Plants. Eudicots: Asterales|url=https://books.google.com/books?id=VhUZnM8S47IC|year=2007|isbn=978-3-540-31051-8|publisher=Springer Science & Business Media|chapter=Heliantheae|pages=440–477}}

• {{cite journal |last1=Barnes |first1=Joanne |last2=Anderson |first2=Linda A |last3=Gibbons |first3=Simon |last4=Phillipson |first4=J David |title=Echinacea species (Echinacea angustifolia (DC.) Hell., Echinacea pallida (Nutt.) Nutt., Echinacea purpurea (L.) Moench): a review of their chemistry, pharmacology and clinical properties |journal=Journal of Pharmacy and Pharmacology|date=August 2005 |volume=57 |issue=8 |pages=929–954 |doi=10.1211/0022357056127|pmid = 16102249 | s2cid = 25151912 | doi-access = free |ref={{harvid|Barnes et al|2005}}}}
• {{cite journal |last1=Hobbs |first1=Christopher |title=Echinacea: A Literature Review: Botany, History, Chemistry, Pharmacology, Toxicology, and Clinical Uses |journal=HerbalGram |date=Winter 1994 |issue=30 |pages=33–48 |url=https://www.herbalgram.org/resources/herbalgram/issues/30/table-of-contents/article702/ }}
• {{cite journal |last1=Hostettmann |first1=K. |title=Geschichte einer Pflanze am Beispiel von Echinacea |trans-title=History of a plant: the example of Echinacea|journal=Complementary Medicine Research |date=2003 |volume=10 |issue=1 |pages=9–12 |doi=10.1159/000071678|pmid=12808356 |s2cid=72348436 |language=de}}
• {{cite journal |last1=Perry |first1=Ann |title=No Easy Answers to Echinacea's Evolution |journal=Agricultural Research |date=March 2010 |volume=58 |issue=3 |page=22 |url=https://agresearchmag.ars.usda.gov/AR/archive/2010/Mar/March2010.pdf }}

;Taxonomy and phylogeny

• {{cite journal |last1=Binns |first1=Shannon E. |last2=Baum |first2=Bernard R. |last3=Arnason |first3=John T. |title=Typification of Echinacea purpurea (L.) Moench (Heliantheae: Asteraceae) and its implications for the correct naming of two Echinacea taxa |journal=Taxon|date=2001 |volume=50 |issue=4 |pages=1169–1175 |doi=10.2307/1224737|jstor=1224737|ref={{harvid|Binns et al|2001}}}}
• {{cite journal |last1=Binns |first1=Shannon E. |last2=Baum |first2=Bernard R. |last3=Arnason |first3=John Thor |title=A Taxonomic Revision of Echinacea (Asteraceae: Heliantheae) |journal=Systematic Botany |date=2002 |volume=27 |issue=3 |pages=610–632 |jstor=3093966 |ref={{harvid|Binns et al|2002}}}}
• {{cite journal |last1=Flagel |first1=L. E. |last2=Rapp |first2=R. A. |last3=Grover |first3=C. E. |last4=Widrlechner |first4=M. P. |last5=Hawkins |first5=J. |last6=Grafenberg |first6=J. L. |last7=Alvarez |first7=I. |last8=Chung |first8=G. Y. |last9=Wendel |first9=J. F. |title=Phylogenetic, morphological, and chemotaxonomic incongruence in the North American endemic genus Echinacea |url=https://core.ac.uk/download/pdf/38934956.pdf |journal=American Journal of Botany |date=1 June 2008 |volume=95 |issue=6 |pages=756–765 |doi=10.3732/ajb.0800049 |pmid=21632401 |hdl=10261/15034 |ref={{harvid|Flagel et al|2008}} }}
• {{cite journal |last1=McGregor |first1=Ronald L |title=The taxonomy of the genus Echinacea (Compositae) |journal=University of Kansas Science Bulletin |date=1968 |volume=48 |pages=113–142 |url=https://archive.org/details/cbarchive_52471_thetaxonomyofthegenusechinacea1902 }}
• {{cite journal |last1=Urbatsch |first1=Lowell E. |last2=Baldwin |first2=Bruce G. |last3=Donoghue |first3=Michael J. |title=Phylogeny of the Coneflowers and Relatives (Heliantheae: Asteraceae) Based on Nuclear rDNA Internal Transcribed Spacer (ITS) Sequences and Chlorplast DNA Restriction Site Data |journal=Systematic Botany |date=July 2000 |volume=25 |issue=3 |pages=539 |doi=10.2307/2666695|jstor=2666695 |s2cid=28581817 |ref={{harvid|Urbatch et al 2000}}}}
• {{cite journal |last1=Zhang |first1=N |last2=Erickson |first2=DL |last3=Ramachandran |first3=P |last4=Ottesen |first4=AR |last5=Timme |first5=RE |last6=Funk |first6=VA |last7=Luo |first7=Y |last8=Handy |first8=SM |title=An analysis of Echinacea chloroplast genomes: Implications for future botanical identification. |journal=Scientific Reports |date=16 March 2017 |volume=7 |issue=1 |pages=216 |doi=10.1038/s41598-017-00321-6 |pmid=28303008|pmc=5428300 |bibcode=2017NatSR...7..216Z }}

;Traditional medicine

• {{cite journal |last1=Ang-Lee |first1=Michael K. |last2=Moss|first2=Jonathan |last3=Yuan |first3=Chun-Su|title=Herbal Medicines and Perioperative Care |journal=JAMA |date=11 July 2001 |volume=286 |issue=2 |pages=208–216 |doi=10.1001/jama.286.2.208| pmid = 11448284|ref={{harvid|Ang-Lee et al|2001}} }}
• {{cite journal |last1=Canlas |first1=Judith |last2=Hudson |first2=James B |last3=Sharma |first3=Manju |last4=Nandan |first4=Devki |title=Echinacea and trypanasomatid parasite interactions: Growth-inhibitory and anti-inflammatory effects of Echinacea |journal=Pharmaceutical Biology |date=September 2010 |volume=48 |issue=9 |pages=1047–1052 |doi=10.3109/13880200903483468| doi-access = free | pmid = 20731557|ref={{harvid|Canlas et al|2010}}}}
• {{cite journal |last1=Hart |first1=Anna |last2=Dey |first2=Paola |title=Echinacea for prevention of the common cold: An illustrative overview of how information from different systematic reviews is summarised on the internet |journal=Preventive Medicine |date=August 2009 |volume=49 |issue=2–3 |pages=78–82 |doi=10.1016/j.ypmed.2009.04.006| pmid = 19389422}}
• {{cite journal |last1=Huntley |first1=Alyson L |last2=Thompson Coon |first2=Joanna |last3=Ernst |first3=Edzard |title=The Safety of Herbal Medicinal Products Derived from Echinacea Species: A Systematic Review |journal=Drug Safety |date=2005 |volume=28 |issue=5 |pages=387–400 |doi=10.2165/00002018-200528050-00003

| pmid = 15853441| s2cid = 25239464|ref={{harvid|Huntley et al|2005}}}}

• {{cite journal |last1=Izzo |first1=Angelo A. |last2=Ernst |first2=Edzard |title=Interactions Between Herbal Medicines and Prescribed Drugs: An Updated Systematic Review |journal=Drugs |date=September 2009 |volume=69 |issue=13 |pages=1777–1798 |doi=10.2165/11317010-000000000-00000| pmid = 19719333| s2cid = 25720882}}
• {{cite journal |last1=Karsch-Völk |first1=Marlies |last2=Barrett |first2=Bruce |last3=Kiefer |first3=David |last4=Bauer |first4=Rudolf |last5=Ardjomand-Woelkart |first5=Karin |last6=Linde |first6=Klaus |title=Echinacea for preventing and treating the common cold |journal=Cochrane Database of Systematic Reviews |date=20 February 2014 | volume = 2 | issue = 2 | pages = CD000530 |doi=10.1002/14651858.CD000530.pub3| pmid = 24554461 | pmc = 4068831|ref={{harvid|Karsch-Volk et al|2014}}}}
• {{cite journal |last1=Mullins |first1=Raymond J |title=Echinacea-associated anaphylaxis |journal=Medical Journal of Australia |date=February 1998 |volume=168 |issue=4 |pages=170–171 |doi=10.5694/j.1326-5377.1998.tb126773.x |pmid = 9507713 | s2cid = 11837168}}
• {{cite journal |last1=Schapowal |first1=A |last2=Klein |first2=P |last3=Johnston |first3=SL |title=Echinacea reduces the risk of recurrent respiratory tract infections and complications: a meta-analysis of randomized controlled trials. |journal=Advances in Therapy |date=March 2015 |volume=32 |issue=3 |pages=187–200 |doi=10.1007/s12325-015-0194-4 |pmid=25784510|s2cid = 1294616|ref={{harvid|Schapowal et al|2015}}}}
• {{cite journal |last1=Shah |first1=Sachin A |last2=Sander |first2=Stephen |last3=White |first3=C Michael |last4=Rinaldi |first4=Mike |last5=Coleman |first5=Craig I |title=Evaluation of echinacea for the prevention and treatment of the common cold: a meta-analysis |journal=The Lancet Infectious Diseases |date=July 2007 |volume=7 |issue=7 |pages=473–480 |doi=10.1016/S1473-3099(07)70160-3|pmid=17597571 |pmc=7106401 |ref={{harvid|Shah et al |2007}}}}
• {{cite journal |last1=Turner |first1=Ronald B. |last2=Bauer |first2=Rudolf |last3=Woelkart |first3=Karin |last4=Hulsey |first4=Thomas C. |last5=Gangemi |first5=J. David |title=An Evaluation of Echinacea angustifolia in Experimental Rhinovirus Infections |journal=New England Journal of Medicine |date=28 July 2005 |volume=353 |issue=4 |pages=341–348 |doi=10.1056/NEJMoa044441|pmid=16049208 |ref={{harvid|Turner et al|2005}}|doi-access=free }}

• {{cite web |last1=Chang |first1=Louise |title=Study: Echinacea Cuts Colds by Half. Skeptic Remains Unconvinced by New Analysis |url=https://www.webmd.com/cold-and-flu/news/20070626/study-echinacea-cuts-colds-by-half |website=WebMD |access-date=12 October 2021 |date=26 June 2007 }}
• {{cite web |last1=Cooperman |first1=Tod |title=Echinacea Supplements Review |url=https://www.consumerlab.com/reviews/echinacea-review/echinacea/ |website=Product reviews |publisher=ConsumerLab |access-date=9 October 2021 |date=17 July 2021 }}* {{cite web |last1=Kindscher |first1=Kelly |title=Conservation planning for Echinacea species |url=https://kindscher.ku.edu/research/medicinal-plants/echinacea/conservation-planning-for-echinacea-species |website=Kansas Biological Survey: Research - medicinal plants |publisher=University of Kansas |access-date=30 September 2021 |date=2021 }}
• {{cite web |last1=Fish and Wildlife Service |author-link=United States Fish and Wildlife Service |title=Endangered and Threatened Wildlife and Plants; Removal of Echinacea tennesseensis (Tennessee Purple Coneflower) From the Federal List of Endangered and Threatened Plants |url=https://www.federalregister.gov/documents/2011/08/03/2011-19674/endangered-and-threatened-wildlife-and-plants-removal-of-echinacea-tennesseensis-tennessee-purple |website=Federal Register |publisher=Department of the Interior |access-date=21 September 2021 |date=3 August 2011 }}
• {{cite web|last=NCCIH|author-link=National Center for Complementary and Integrative Health|title=Echinacea|url=http://nccih.nih.gov/health/echinacea/ataglance.htm|publisher=US National Institutes of Health|date=July 2020|access-date=17 September 2021}}
• {{cite web|last=NCCIH|author-link=National Center for Complementary and Integrative Health|title=The Common Cold and Complementary Health Approaches: What the Science Says|url=https://www.nccih.nih.gov/health/providers/digest/the-common-cold-and-complementary-health-approaches-science|publisher=US National Institutes of Health|date=December 2020a|access-date=25 September 2021}}
• {{cite web|last=Drugsite|author-link=Drugs.com|title=Echinacea Uses, Benefits & Dosage - Drugs.com Herbal Database|url=https://www.drugs.com/npp/echinacea.html|website=Drugs.com|publisher=Drugsite Trust|location=New Zealand|access-date=29 September 2021|date=8 April 2021}}
• {{cite web|last=Cancer Research UK|author-link=Cancer Research UK|title=Echinacea|url=https://www.cancerresearchuk.org/about-cancer/treatment/complementary-alternative-therapies/individual-therapies/echinacea|website=Complementary and alternative therapies|access-date=4 October 2021|date=18 January 2019}}
• {{cite web |last1=Natural Standard Research Collaboration |author-link=Natural Standard Research Collaboration |title=Echinacea (Echinacea angustifolia, Echinacea pallida, Echinacea purpurea) |url=http://www.mayoclinic.org/drugs-supplements/echinacea/safety/HRB-20059246 |website=Drugs and supplements |publisher=Mayo Clinic |access-date=4 October 2021 |archive-url=https://web.archive.org/web/20170708015252/http://www.mayoclinic.org/drugs-supplements/echinacea/safety/HRB-20059246 |archive-date=8 July 2017 |date=1 November 2013 }}
• {{cite web |last1=MHRA |author-link=Medicines and Healthcare products Regulatory Agency |title=Echinacea herbal products should not be used in children under 12 years old |url=https://webarchive.nationalarchives.gov.uk/ukgwa/20141206003656/http://www.mhra.gov.uk/NewsCentre/Pressreleases/CON180627 |website=The National Archives |type=Press release |access-date=9 October 2021 |date=20 August 2014 }}
• {{cite web |last1=FDA |author-link=FDA |title=What You Need to Know about Dietary Supplements |url=https://www.fda.gov/food/buy-store-serve-safe-food/what-you-need-know-about-dietary-supplements |website=Food: Consumers |access-date=9 October 2021 |date=29 November 2017 }}

;Databases and floras

• {{cite web |last1=McCoy |first1=Ann |last2=Widrlechner |first2=Mark |last3=Carstens |first3=Jeff |title=A Comprehensive Echinacea Germplasm Collection Located at the North Central Regional Plant Introduction Station |url=https://www.ars.usda.gov/ARSUserFiles/50301000/Posters/Echinacea_poster2.pdf |website=Iowa Botanical Supplement Research Center |publisher=USDA/ARS, Iowa State University, Ames |access-date=10 October 2021 |date=October 2005 |type=Conference poster |ref={{harvid|McCoy et al|2005}} }}{{link note|note=[https://lib.dr.iastate.edu/ncrpis_conf/29/ Fifty-Fifth Annual Meeting of the Eastern Region of the International Plant Propagators' Society]}}
• {{cite web |last1=Urbatsch |first1=Lowell E. |last2=Neubig |first2=Kurt M. |last3=Cox |first3=Patricia B. |title=Echinacea Moench, Methodus. 591. 1794. |url=http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=111203 |access-date=23 September 2021 |work=Flora of North America |year=2006 |volume=21 |page=88 |publisher=Oxford University Press |location=New York |ref={{harvid|Urbatsch et al|2006}} }}
• {{cite web|title=Echinacea purpurea (L.) Moench|website=Tropicos|url=https://www.tropicos.org/name/2710007|publisher=Missouri Botanical Garden|access-date=14 September 2021|date=2021|ref={{harvid|Tropicos|2021}}}}
• {{cite web|last=POWO|author-link=Plants of the World Online|title=Echinacea Moench|url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30035795-2|website=Plants of the World Online|publisher=Royal Botanic Gardens, Kew|date=2021|access-date=19 September 2021}}
• {{cite web|last=WFO|author-link=World Flora Online|title=Echinacea|url=http://www.worldfloraonline.org/taxon/wfo-4000012904|access-date=15 September 2021|date=2021}}

{{Refend}}

• {{Commons category-inline}}
• {{Wikispecies-inline|Echinacea (Asteraceae)|Echinacea}}

{{Unproven and disproven cancer treatments|state=collapsed}}

{{Taxonbar|from=Q1642983}}

{{Authority control}}

Category:Plants used in traditional Native American medicine

Category:Alternative cancer treatments

Category:Asteraceae genera

Category:Flora of Northern America

Category:Taxa named by Conrad Moench