Echinacea has a very unimpressive track record despite its widespread popularity.  It is heavily promoted in alternative medicine circles, although not because there is any significant research evidence of value.  As you will note below, many studies have been done with minimal evidence of any value.  Echinacea may be of value, but if it is, its benefit is quite minor.  For my recommendations, see The Common Cold.

Three Different Echinacea Preparations All Failed to Prevent or Help Colds: Three preparations of echinacea, with distinct phytochemical profiles, were produced by extraction from E. angustifolia roots with supercritical carbon dioxide, 60 percent ethanol, or 20 percent ethanol. A total of 437 volunteers were randomly assigned to receive either prophylaxis (beginning seven days before the virus challenge) or treatment (beginning at the time of the challenge) either with one of these preparations or with placebo. The results for 399 volunteers who were challenged with rhinovirus type 39 and observed in a sequestered setting for five days were included in the data analysis. There were no statistically significant effects of the three echinacea extracts on rates of infection or severity of symptoms. Similarly, there were no significant effects of treatment on the volume of nasal secretions, on polymorphonuclear leukocyte or interleukin-8 concentrations in nasal-lavage specimens, or on quantitative-virus titer. An evaluation of Echinacea angustifolia in experimental rhinovirus infections. Turner RB, et al. University of Virginia School of Medicine, Charlottesville. N Engl J Med. 2005 Jul 28;353(4):341-8. Ed: Previous research has suggested that echinacea has at most minor benefit with many studies finding no benefit.

Echinacea No Help to Children with Colds: In a large DB PC study of 407 children and 707 colds, Univ. of Washington researchers found no benefit from echinacea but an increase in rashes in the echinacea group. Children started echinacea as soon as they had two cold symptoms. Over 80% of children had at least one cold over the 4 months of the study and the average duration was 9 days. There was a very slight trend for the placebo to do better. Efficacy and safety of echinacea in treating upper respiratory tract infections in children: a randomized controlled trial. Taylor JA, Weber W, Standish L, Quinn H, Goesling J, McGann M, Calabrese C. JAMA. 2003 Dec 3;290(21):2824-30

Echinacea No Benefit Prevention URIs: DB PC 109 pt 8 weeks. No effect on incidence, duration or severity of URIs. W. Grimm & H-H Mueller, Am J Med ’99;106:138.

Echinacea Not Help Prevention Colds: DB 302 adults 12 weeks echinacea purpurea root or echinacea angustifolia roots or placebo. No significant delay of time to first URI although possible 10-15% beneficial effect when considering the results of this and two other studies with this study finding 29.3%, 32% and 36.7% getting colds with delays of 69, 66, and 65 days. Arch Fam Med 11/98 7:541-4 Melchart D, Techniche Universitat, Munich. This study is used by herb industry to promote sales! Energy Times 2/99 p30

Echinacea Claimed Benefit Treating URIs by German Studies: Many studies published. Med Letter questions quality of all. 1000 pt DB PC E. pallida root. Braunig, Naturheilpraxis mit Naturmedizin ’93;1:72; M Dorn, Complement Ther Med ’97;3:40; E. purpurea juice: B Schulten et al, Arzneimittelforschung ’01;51:563

Echinacea in Five Studies Not Impressive for Immune Stimulation: 4 DB placebo studies with healthy volunteers, 134 in all. Measuring immunomodulatory activity with relative phagocytic activity of polymorphonuclear neutophil granulocytes and # WBCs in venous blood. No S-E. Three studies found nothing, one a 23% and another a 54% incr in phagocytic stimulation. U Munchen, D Melchart, J Altern Complement Med ’95;1:145-60

Echinacea No Benefit for Colds: DB PC 148 U Wisc. Started Echinacea 1^st day of cold six times then tid for up to nine more days. Actually, placebo did non-significantly better. Ann Intern Med 2002 Dec 17;137(12):939-46

Echinacea Helps Common Cold in DB: Cologne 880 adults DB PC 6.0 vs 9.0 days to symptom resolution. Efficacy of Echinacea purpurea in patients with a common cold. A placebo-controlled, randomised, double-blind clinical trial. Schulten B, Bulitta M, Ballering-Bruhl B, Koster U, Schafer M. Arzneimittelforschung. 2001;51(7):563-8

Echinacea Tea Helped Colds in DB: 95 students 90 days study 5-6 cups per day for up to five days at first symptoms of a cold or flu. p<.001 favoring rx. DB PC. The efficacy of echinacea compound herbal tea preparation on the severity and duration of upper respiratory and flu symptoms: a randomized, double-blind placebo-controlled study. Lindenmuth GF, Lindenmuth EB J Altern Complement Med. 2000 Aug;6(4):327-34; purple coneflower, is an herbal medicine that has been used for centuries, customarily as a treatment for the common cold, coughs, bronchitis, upper respiratory infections, and some inflammatory conditions.

Echinacea Only Trend in Favor for Colds in DB: MUSC study with rhinovirus 23 innoculated in DB PC study into over 100 healthy college students who had taken echinacea 300 tid or placebo for 14 days as preventative. No significant difference tho mild trends favoring echinacea: Infection occurred in 44 and 57% and illness occurred in 36 and 43% of the echinacea- and placebo-treated. Similar trend favoring echinacea in intensity of symptoms. Ineffectiveness of echinacea for prevention of experimental rhinovirus colds. Turner RB, Riker DK, Gangemi JD. Antimicrob Agents Chemother. 2000 Jun;44(6):1708-9

Echinacea Review Says Unclear if Works for Colds: Twelve clinical studies published from 1961-1997 concluded that echinacea was efficacious for treating the common cold, but the results are unclear due to inherent flaws in study design. Five trials were published since 1997; two showed that echinacea lacked efficacy for treating and preventing URTI symptoms, and three concluded that it was effective in reducing the frequency, duration, and severity of common cold symptoms. Pharmacotherapy. 2000 Jun;20(6):690-7

Echinacea Review Favors Cold Treatment: German review found 8 prevention and 8 treatment studies with common cold covering 3,396 subjects. Echinacea for preventing and treating the common cold. Melchart D, Linde K, Fischer P, Kaesmayr J. Cochrane Database Syst Rev. 2000;(2):CD000530. Says majority of studies find significant benefit.

Echinacea Brand Said Better for Colds than Others in DB: Phytomedicine. 1999 Mar;6(1):1-6. Sweden. Probably funded by manufacturer of Echinaforce. No data in abstract.

Viracea: Good antiviral activity against Acyclovir resistant and susceptible strains of HSV-1 and HSV-2 in vitro. From Echinacea purpurea. Antiviral Res 7/98, 39:55-61.