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Medically reviewed on April 16, 2018

Scientific Name(s): Echinacea angustifolia DC, Echinacea purpurea (L.) Moench, and Echinacea pallida (Nutt.) Britton. Family: Asteraceae (sunflowers)

Common Name(s): American coneflower , black Sampson , black Susan , comb flower , echinaceawurzel , hedgehog , igelkopfwurzel , Indian head , Kansas snakeroot , narrow-leaved purple coneflower , purple coneflower , purpursonnenhutkraut , racine d'echininacea , rock-up-hat , roter sonnenhut , scurvy root , snakeroot , sonnenhutwurzel


There is limited evidence that echinacea is effective in shortening the duration of symptoms of upper respiratory tract infections, but a lack of effectiveness for its use in prevention. Echinacea is hypothesized to be an immunomodulator. There is also interest in its potential use in cancer therapy, but clinical trials are lacking. The variation in available commercial products and lack of consistency in clinical trials make specific recommendations difficult.


Many commercial preparations are available containing components derived from different plant parts as well as from different species and varieties. Recommended dosing (all administered 3 times daily) include the following: 300 mg dry powdered extract (standardized to 3.5% echinacoside), 0.25 to 1.25 mL liquid extract (1:1 in 45% alcohol), 1 to 2 mL tincture (1:5 in 45% alcohol), 2 to 3 mL expressed juice of E. purpurea , and 0.5 to 1 g dried root or tea. Echinacea use for more than 8 weeks at a time should be avoided because of the potential for immune suppression. Intravenous (IV) use is not recommended.


Known hypersensitivity to plants of the Asteraceae/Compositae family; any condition in which immune stimulation or suppression would be considered disadvantageous.


Limited clinical evidence, expert opinion, and long-term traditional use suggest that oral echinacea is safe for use during pregnancy at normal dosages. Direct evidence for safety during lactation is lacking. Use with caution.


Specific case reports of interactions are lacking, and limited, conflicting data regarding effects on the cytochrome P450 (CYP-450) enzyme system have been published.

Adverse Reactions

Adverse reactions are rare. In clinical trials, adverse reactions caused by echinacea were generally not statistically significant compared with placebo. The most commonly reported reactions were allergy, GI upset, and rash. Individuals with allergy to ragweed or related allergens should use echinacea with caution. A case report of leukopenia, possibly caused by long-term use of echinacea, has been published. Potential immune suppression with long-term use has been suggested.


Little is known about the toxicity of echinacea. Animal studies generally indicate low toxicity.


There are at least 9 species of Echinacea . 1 Those most commonly used medicinally are E. purpurea , E. pallida , and E. angustifolia . 2 , 3 Echinacea is native to the United States, specifically Kansas, Nebraska, and Missouri. Because of confusion regarding the identification of echinacea species, much of the early European research conducted on this plant, particularly E. angustifolia , may have been conducted on E. pallida . 4 E. angustifolia and E. purpurea are perennial herbs with narrow leaves and stout stems that grow from 90 cm to 1.2 m in height that blossom as a single lavender or purple flower head. When chewed, the plant imparts a pungent taste and causes tingling of the lips and tongue. 1


Echinacea is a popular herbal remedy in the United States. The plant was used in traditional medicine by American Indians and quickly adopted by settlers. During the 1800s, claims for the curative properties of the plant ranged from blood purification to treatment of dizziness and rattlesnake bites. During the early part of the 20th century, extracts of the plant were used as anti-infectives; however, the use of these products fell out of favor after the discovery of modern antibiotics. The plant and its extracts continue to be used topically for wound healing and internally to stimulate the immune system. 5 , 6


There is general agreement that no single chemical constituent is responsible for echinacea's biological activity. 3 , 7 Most studies indicate that the lipophilic fraction of the root and leaves contains the most potent immunostimulating components. 7 Many alkamides, predominantly isobutylamides, have been described. 8 Caffeic acid glycosides and esters (eg, echinacoside, cynarin, cichoric acid) are found in the root and aerial parts of the plants, but echinoside is not found in E. purpurea . 3 Polysaccharides have been identified in E. purpurea aerial parts and E. pallida root. 3

The alkamides found in echinacea are available following oral administration, whereas the caffeic acid derivatives are not. 3 The pungent component of the plant is echinacein, an isobutylamide. 9 Depending on the species, the essential oil obtained from the root may be high in unsaturated alkyl ketones or isobutylamides. 4

Uses and Pharmacology


Root extract from 3 echinacea species ( E. purpurea , E. angustifolia , and E. pallida ) showed concentration- and time-dependent induction of apoptosis in human pancreatic and colon cancer cell lines. 10

Animal data

In mice, the mean survival age was prolonged and thymic lymphoma enlargement suppressed with 8 weeks of echinacea therapy, while other experiments have demonstrated elevated natural killer cell levels and prolonged survival times in leukemic mice. 11 , 12 Dietary supplementation with E. purpurea in rats undergoing experimental irradiation resulted in the mobilization and enhancement of vitamin E–mediated oxidation/reduction pathways, suggesting that echinacea may have potential as a radioprotector. 13 However, another study in rats showed that coadministration of cadmium and echinacea lead to a concentration of cadmium in certain organs and blood. 14 An in vitro study demonstrated that typical constituents of echinacea species applied topically were effective in the prevention and/or treatment of skin damage caused by ultraviolet/ultraviolet B radiation, 15 and another study suggested radioprotection following oral administration of echinacea by radiology technicians. 16

Clinical data

In a trial investigating the effects of an IV-administered polysaccharide fraction of echinacea among patients with advanced gastric cancer, increases in the median number of leukocytes was demonstrated; however, the differences were not considered clinically relevant. 17 Another study involving 23 patients with tumors showed no effect on cytokine or leukocytes after using a preparation of E. angustifolia . 18


Many studies investigating immunomodulatory properties have been conducted with different Echinacea species, extracts, and plant parts. However, there is little agreement on which chemical constituents are responsible for activity on the immune system. 3 , 19 , 20 Enhanced macrophage function, stimulation of cytokine production (including certain interleukins and tumor necrosis factor alpha), enhanced natural-killer function, and increased mean circulating total white blood cell counts have all been demonstrated in vitro. 3 , 21 , 22 , 23 , 24 , 25 , 26 , 27

Clinical data

In healthy adults, stimulation of the immune system via the CD69 marker was demonstrated within 24 hours of echinacea ingestion. 28 A study in humans found changes in CD8, T lymphocytes, and natural killer cells, but not in other lymphocyte subpopulations. 29 Another study found that echinacea extract stimulated cell-mediated immunity in humans following a single dose, but repeated daily doses suppressed the immune response. 30 A study in healthy adults found that echinacea attenuated the suppression of exercise-induced mucosal immune response. 31 A consensus statement on the lack of evidence to support the use of echinacea among athletes to maintain immune health has been published. 32

Upper respiratory tract infection

In vitro studies suggest activity of echinacea extracts against some respiratory bacteria and viruses. 33

Animal data

The widespread traditional use of echinacea for the common cold and the availability of clinical trial data make animal data mostly irrelevant. 33

Clinical data

A few quality meta-analyses have been published on the effect of echinacea on the management of the common cold. All have emphasized methodological issues within individual clinical trials, such as variations in preparation and dosage used, outcomes measuring high dropout rates, and lack of intention-to-treat analyses, making comparisons difficult. 34 , 35 , 36 Evidence regarding a definitive place in therapy remains weak. In comparing echinacea with placebo, a Cochrane review found an effect in 9 trials, a trend in 1 trial, and no effect in 6 trials. Most of the included trials studied E. purpurea . 35 Other reviews found a trend toward beneficial effects, but variations in trial data make definitive statements about effect difficult. 34 , 37 , 38 , 39 One study evaluated the placebo effect in treating the common cold and found decreased duration and severity of symptoms among a subgroup of participants who believed in echinacea, regardless of whether or not they had received echinacea or placebo. 40 Clinical trials continue to be undertaken with results remaining equivocal. 41 , 42 One clinical study in otitis media suggested an increased risk of disease in echinacea-treated children. 43


The analyses of trial data for the prevention of colds are less compelling in their conclusions than those of treatment. However, variations in the delay between appearance of cold symptoms and taking the preparation may add to the difficulty in making comparisons. 44 The Cochrane meta-analysis included data from 3 trials and found no difference between echinacea and placebo. 35 In 2 additional reviews, trial data excluded from the Cochrane meta-analysis showed a trend toward benefit in the prevention of colds. 39 , 44 All reviewers concluded that more rigorous trials are required. 35 , 39 , 44

Other uses

Echinacea's in vitro activity against herpes simplex virus, HIV, and influenza has been described for E. purpurea extracts. 33 , 45 , 46 A clinical trial investigating the effect of echinacea on the severity and recurrence of genital herpes found no difference over placebo. Antifungal and antibacterial properties have also been described, but clinical trials are lacking. 3 , 24


When injected IV in mice or rats, echinacea extract almost completely inhibited carrageenan-induced mice or rat paw edema. Similarly, when the extract was applied topically, it almost completely inhibited the inflammation induced by croton oil applied to the mice or rat ears. 47 Activity of echinacea was slightly less than that of topical indomethacin. Several caffeoyl conjugates isolated from E. angustifolia , including chicoric acid, cynarine, chlorogenic acid, and caftaric acid, demonstrate antihyaluronidase activity. 48 Alkamides from E. angustifolia exhibited cyclooxygenase-2–dependent prostaglandin E 2 inhibition in laboratory experiments. 26 , 46 , 49


Cream and gel echinacea preparations demonstrated skin hydrating and antiwrinkle properties in a small clinical study. 50 Echinacea exhibited in vitro antibacterial activity against clinical strains of Propionibacterium acnes , suggesting a role in the management of acne. 51


A major limitation reported in the meta-analyses of available trial data was the lack of standardization of echinacea preparations. Many products lacked active echinacea chemical compounds or were contaminated with other chemical entities. 3 , 34 , 35

Recommended dosing (all administered 3 times daily) includes 300 mg dry powdered extract (standardized to echinacoside 3.5%), 0.25 to 1.25 mL liquid extract (1:1 in alcohol 45%), 1 to 2 mL tincture (1:5 in alcohol 45%), 2 to 3 mL expressed juice of E. purpurea , and 0.5 to 1 g dried root or tea. 52 Safety and tolerability have been studied in children. 43 , 53

Intravenous use of echinacea is not recommended. 13 Echinacea use for more than 8 weeks at a time should be avoided because of the potential for immune suppression. 35 , 52 , 54


A prospective cohort study (N = 206) found no increased risk of fetal malformations with the use of echinacea during the first trimester, 55 but was limited by small sample size, allowance of detection of common malformations only, and lack of standardization of preparations. 3 , 56 Evidence for the safe use of echinacea during pregnancy is lacking; however, the Complete German Commission E Compendium Monographs considers oral echinacea safe for use during pregnancy and lactation in normal recommended dosages. 6 , 52


Specific case reports of interactions are lacking, and limited, conflicting data regarding effects on the CYP-450 enzyme system have been published. 3 , 57 , 58 , 59 Studies have shown no clinically important effects of coadministration of echinacea with digoxin, 59 warfarin, 60 darunavir, lopinavir, or ritonavir. 61 , 62 A theoretical interaction with immunosuppressant drugs has been postulated due to immunomodulatory activity described for echinacea. 45

Adverse Reactions

Adverse reactions for echinacea are not commonly reported despite widespread use and are observed as frequently as with placebo in clinical trials. 34 , 45 The most commonly reported are allergic reactions (including a case report of immunoglobulin E–related eosinophilia), GI upset, and rash. Individuals with allergy to ragweed, chrysanthemum, marigold, daisies, or related allergens should use echinacea with caution. 45 , 52 , 63

A case report of leukopenia, possibly caused by long-term use of echinacea, has been published, 54 while a case of reversible acute cholestatic autoimmune hepatitis has been attributed to echinacea consumption. 64 In a trial conducted among patients with advanced gastric cancer, an association with the use of IV E. purpurea extract could not be ruled out in the deaths of 2 patients. 17

Debate exists regarding the appropriateness of echinacea use in patients with autoimmune disorders, and until clarified, echinacea should not be used in any condition in which immune stimulation or suppression would be considered disadvantageous, such as HIV, tuberculosis, multiple sclerosis, and immunosuppressive therapy. 45 , 65


Little is known about the toxicity of echinacea, despite its widespread use. It has been documented in traditional American medicine for more than a century and generally has not been associated with acute or chronic toxicity. 3 Purified echinacea polysaccharide is relatively nontoxic. Toxicity studies found that doses of arabinogalactan as high as 4 g/kg injected intraperitoneally or IV were essentially devoid of toxic effects. 22 High-dose oral and IV administration (ie, several times the normal human therapeutic dose) of the expressed juice of E. purpurea to rodents for 4 weeks demonstrated no acute, subacute, genotoxic, carcinogenic, mutagenic, or other toxic reactions. 66


1. Echinacea angustifolia DC. USDA, NRCS. 2007. The PLANTS Database ( , 2 April 2012). National Plant Data Team, Greensboro, NC 27401–4901 USA. Accessed April 4, 2012.
2. Chavez M , et al. Echinacea . Hosp Pharm . 1998;33:180-188.
3. Barnes J , Anderson LA , Gibbons S , Phillipson JD . Echinacea species ( Echinacea angustifolia (DC.) Hell., Echinacea pallida (Nutt.) Nutt., Echinacea purpurea (L.) (Moench): a review of their chemistry, pharmacology and clinical properties . J Pharm Pharmacol . 2005;57(8):929-954.
4. Bauer R , Khan IA , Wagner H . TLC and HPLC analysis of Echinacea pallida and E. angustifolia roots . Planta Med . 1988;54(5):426-430.
5. Tyler V . The New Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies . 2nd ed. Philadelphia, PA: GF Stickley Co; 1987.
6. Perri D , Dugoua JJ , Mills E , Koren G . Safety and efficacy of echinacea ( Echinacea angustafolia , E. purpurea and E. pallida ) during pregnancy and lactation . Can J Clin Pharmacol . 2006;13(3):e262-e267.
7. Müller-Jakic B , Breu W , Pröbstle A , Redl K , Greger H , Bauer R . In vitro inhibition of cyclooxygenase and 5-lipoxygenase by alkamides from echinacea and achillea species . Planta Med . 1994;60(1):37-40.
8. Bauer R , Remiger P , Wagner H . New alkamides from Echinacea angustifolia and E. purpurea Roots . Planta Med . 1988;54(6):563-564.
9. Jacobson M . The structure of echinacein, the insecticidal component of American coneflower roots . J Org Chem . 1967;32(5):1646-1647.
10. Chicca A , Adinolfi B , Martinotti E , et al. Cytotoxic effects of Echinacea root hexanic extracts on human cancer cell lines . J Ethnopharmacol . 2007;110(1):148-153.
11. Currier NL , Miller SC . Echinacea purpurea and melatonin augment natural-killer cells in leukemic mice and prolong life span . J Altern Complement Med . 2001:7(3):241-251.
12. Miller SC . Echinacea: a miracle herb against aging and cancer? Evidence in vivo in mice . Evid Based Complement Alternat Med . 2005;2(3):309-314.
13. Paranich AV , Pocherniaeva VF , Dubinskaia GM , et al. Effect of supposed radioprotectors on oxidation-reduction of vitamin E in the tissues of irradiated rats [in Russian] . Radiats Biol Radioecol . 1993;33(5):653-657.
14. Zitkevicius V, Smalinskiene A, Lesauskaite V, et al. Influence of Echinacea purpurea (L.) Moench extract on the toxicity of cadmium. Ann N Y Acad Sci . 2007;1095:585-592.
15. Facino R , Carini M , Aldini G , Saibene L , Pietta P , Mauri P . Echinacoside and caffeoyl conjugates protect collagen from free radical-induced degradation: a potential use of echinacea extracts in the prevention of skin photodamage . Planta Med . 1995;61(6):510-514.
16. Joksić G, Petrović S, Joksić I, Leskovac A. Biological effects of Echinacea purpurea on human blood cells. Arh Hig Rada Toksikol . 2009;60(2):165-172.
17. Melchart D , Clemm C , Weber B , et al. Polysaccharides isolated from Echinacea purpurea herba cell cultures to counteract undesired effects of chemotherapy—a pilot study . Phytother Res . 2002;16(2):138-142.
18. Elsässer-Beile U , Willenbacher W , Bartsch HH , Gallati H , Schulte Mönting J , von Kleist S . Cytokine production in leukocyte cultures during therapy with echinacea extract . J Clin Lab Anal . 1996;10(6):441-445.
19. Bauer VR , Jurcic K , Puhlmann J , Wagner H . Immunologic in vivo and in vitro studies on echinacea extracts [in German] . Arzneimittelforschung . 1988;38(2):276-281.
20. Wu L, Rowe EW, Jeftinija K, et al. Echinacea-induced cytosolic Ca2+ elevation in HEK293. BMC Complement Altern Med . 2010;10:72.
21. Agnew LL , Guffogg SP , Matthias A , Lehmann RP , Bone KM , Watson K . Echinacea intake induces an immune response through altered expression of leucocyte hsp70, increased white cell counts and improved erythrocyte antioxidant defences . J Clin Pharm Ther . 2005;30(4):363-369.
22. Luettig B , Steinmüller C , Gifford GE , Wagner H , Lohmann-Matthes ML . Macrophage activation by the polysaccharide arabinogalactan isolated from plant cell cultures of Echinacea purpurea . J Nat Cancer Inst . 1989;81(9):669-675.
23. Steinmüller C , Roesler J , Gröttrup E , Franke G , Wagner H , Lohmann-Matthes ML . Polysaccharides isolated from plant cell cultures of Echinacea purpurea enhance the resistance of immunosuppressed mice against systemic infections with Candida albicans and Listeria monocytogenes . Int J Immunopharmacol . 1993;15(5):605-614.
24. Ghaemi A, Soleimanjahi H, Gill P, Arefian E, Soudi S, Hassan Z. Echinacea purpurea polysaccharide reduces the latency rate in herpes simplex virus type-1 infections. Intervirology . 2009;52(1):29-34.
25. Chicca A, Raduner S, Pellati F, et al. Synergistic immunomopharmacological effects of N-alkylamides in Echinacea purpurea herbal extracts. Int Immunopharmacol . 2009;9(7-8):850-858.
26. Guiotto P, Woelkart K, Grabnar I, et al. Pharmacokinetics and immunomodulatory effects of phytotherapeutic lozenges (bonbons) with Echinacea purpurea extract. Phytomedicine . 2008;15(8):547-554.
27. Ritchie MR, Gertsch J, Klein P, Schoop R. Effects of Echinaforce treatment on ex vivo-stimulated blood cells. Phytomedicine . 2011;18(10):826-831.
28. Brush J , Mendenhall E , Guggenheim A , et al. The effect of Echinacea purpurea , Astragalus membranaceus and Glycyrrhiza glabra on CD69 expression and immune cell activation in humans . Phytother Res . 2006;20(8):687-695.
29. Schwarz E , Parlesak A , Henneicke-von Zepelin HH , Bode JC , Bode C . Effect of oral administration of freshly pressed juice of Echinacea purpurea on the number of various subpopulations of B- and T-lymphocytes in healthy volunteers: results of a double-blind, placebo-controlled cross-over study . Phytomedicine . 2005;12(9):625-631.
30. Coeugniet E , Elek E . Immunomodulation with Viscum album and Echinacea purpurea extracts . Onkologie . 1987;10(suppl 3):27-33.
31. Hall H , Fahlman MM , Engels HJ . Echinacea purpurea and mucosal immunity . Int J Sports Med . 2007;28(9):792-797.
32. Walsh NP, Gleeson M, Pyne DB, et al. Position statement. Part two: Maintaining immune health. Exerc Immunol Rev . 2011;17:64-103.
33. Sharma M, Anderson SA, Schoop R, Hudson JB. Induction of multiple pro-inflammatory cytokines by respiratory viruses and reversal by standardized Echinacea, a potent antiviral herbal extract. Antiviral Res . 2009;83(2):165-170.
34. Islam J , Carter R . Use of Echinacea in upper respiratory tract infection . South Med J . 2005;98(3):311-318.
35. Linde K , Barrett B , Wölkart K , Bauer R , Melchart D . Echinacea for preventing and treating the common cold . Cochrane Database Syst Rev . 2006;(1):CD000530.
36. von Maxen A, Schoenhoefer PS. Benefit of echinacea for the prevention and treatment of the common cold? Lancet Infect Dis . 2008;8(6):346-347; author reply 347-348.
37. Caruso TJ , Gwaltney JM Jr . Treatment of the common cold with echinacea: a structured review . Clin Infect Dis . 2005;40(6):807-810.
38. Koenig K , Roehr CC . Does treatment with Echinacea purpurea effectively shorten the course of upper respiratory tract infections in children? Arch Dis Child . 2006:91(6):535-537.
39. Shah SA , Sander S , White CM , Rinaldi M , Coleman CI . Evaluation of echinacea for the prevention and treatment of the common cold: a meta-analysis . Lancet Infect Dis . 2007;7(7):473-480.
40. Barrett B, Brown R, Rakel D, et al. Placebo effects and the common cold: a randomized controlled trial. Ann Fam Med . 2011;9(4):312-322.
41. Barrett B, Brown R, Rakel D, et al. Echinacea for treating the common cold: a randomized trial. Ann Intern Med . 2010;153(12):769-777.
42. O'Neil J, Hughes S, Lourie A, Zweifler J. Effects of echinacea on the frequency of upper respiratory tract symptoms: a randomized, double-blind, placebo-controlled trial. Ann Allergy Asthma Immunol . 2008;100(4):384-388.
43. Wahl RA, Aldous MB, Worden KA, Grant KL. Echinacea purpurea and osteopathic manipulative treatment in children with recurrent otitis media: a randomized controlled trial. BMC Complement Altern Med . 2008;8:56.
44. Schoop R , Klein P , Suter A , Johnston SL . Echinacea in the prevention of induced rhinovirus colds: a meta-analysis . Clin Ther . 2006:28(2):174-183.
45. Barnes J. Echinacea. J Prim Health Care . 2009;1(2):146-147.
46. Birt DF, Widrlechner MP, Lalone CA, et al. Echinacea in infection. Am J Clin Nutr . 2008;87(2):488S-492S.
47. Tubaro A , Tragni E , Del Negro P , Galli CL , Della Loggia R . Anti-inflammatory activity of a polysaccharidic fraction of Echinacea angustifolia . J Pharm Pharmacol . 1987;39(7):567-569.
48. Facino RM , Carini M , Aldini G , et al. Direct characterization of caffeoyl esters with antihyaluronidase activity in crude extracts from Echinacea angustifolia roots by fast atom bombardment tandem mass spectrometry . Farmaco . 1993;48(10):1447-1461.
49. Hinz B , Woelkart K , Bauer R . Alkamides from Echinacea inhibit cyclooxygenase-2 activity in human neuroglioma cells . Biochem Biophys Res Commun . 2007;360(2):441-446.
50. Yotsawimonwat S, Rattanadechsakul J, Rattanadechsakul P, Okonogi S. Skin improvement and stability of Echinacea purpurea dermatological formulations. Int J Cosmet Sci . 2010;32(5):340-346.
51. Sharma M, Schoop R, Suter A, Hudson JB. The potential use of Echinacea in acne: control of Propionibacterium acnes growth and inflammation. Phytother Res . 2011;25(4):517-521.
52. Blumenthal M , Busse WR, eds. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines . Austin, TX: American Botanical Council; Boston, MA: Integrative Medicine Communications; 1998.
53. Saunders PR, Smith F, Schusky RW. Echinacea purpurea L. in children: safety, tolerability, compliance, and clinical effectiveness in upper respiratory tract infections. Can J Physiol Pharmacol . 2007;85(11):1195-1199.
54. Kemp DE , Franco KN . Possible leukopenia associated with long-term use of echinacea . J Am Board Fam Pract . 2002:15(5):417-419.
55. Gallo M , Sarkar M , Au W , et al. Pregnancy outcome following gestational exposure to echinacea: a prospective controlled study . Arch Intern Med . 2000;160(20):3141-3143.
56. Holst L, Wright D, Haavik S, Nordeng H. Safety and efficacy of herbal remedies in obstetrics-review and clinical implications. Midwifery . 2011;27(1):80-86.
57. Freeman C, Spelman K. A critical evaluation of drug interactions with Echinacea spp. Mol Nutr Food Res . 2008;52(7):789-798.
58. Colalto C. Herbal interactions on absorption of drugs: Mechanisms of action and clinical risk assessment. Pharmacol Res . 2010;62(3):207-227.
59. Izzo AA, Ernst E. Interactions between herbal medicines and prescribed drugs: an updated systematic review. Drugs . 2009;69(13):1777-1798
60. Abdul MI, Jiang X, Williams KM, et al. Pharmacokinetic and pharmacodynamic interactions of echinacea and policosanol with warfarin in healthy subjects. Br J Clin Pharmacol . 2010;69(5):508-515.
61. Moltó J, Valle M, Miranda C, et al. Herb-drug interaction between Echinacea purpurea and darunavir-ritonavir in HIV-infected patients. Antimicrob Agents Chemother . 2011;55(1):326-330.
62. Penzak SR, Robertson SM, Hunt JD, et al. Echinacea purpurea significantly induces cytochrome P450 3A activity but does not alter lopinavir-ritonavir exposure in healthy subjects. Pharmacotherapy . 2010;30(8):797-805.
63. Maskatia ZK, Baker K. Hypereosinophilia associated with echinacea use. South Med J . 2010;103(11):1173-1174.
64. Kocaman O, Hulagu S, Senturk O. Echinacea-induced severe acute hepatitis with features of cholestatic autoimmune hepatitis. Eur J Intern Med . 2008;19(2):148.
65. Mistrangelo M, Cornaglia S, Pizzio M, et al. Immunostimulation to reduce recurrence after surgery for anal condyloma acuminata: a prospective randomized controlled trial. Colorectal Dis . 2010;12(8):799-803.
66. Mengs U , Clare CB , Poiley JA . Toxicity of Echinacea purpurea . Acute, subacute, and genotoxicity studies . Arzneimittelforschung . 1991;41(10):1076-1081.

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