title: Echinacea for treating the common cold: a randomized trial.
abstract: BACKGROUND
  Echinacea is widely used to treat the common cold.
  
  
  OBJECTIVE
  To assess the potential benefits of echinacea as a treatment of common cold.
  
  
  METHODS
  Randomized, controlled trial. (ClinicalTrials.gov registration number: NCT00065715)
  
  
  METHODS
  Dane County, Wisconsin.
  
  
  METHODS
  719 patients, aged 12 to 80 years, with new-onset common cold.
  
  
  METHODS
  Patients were assigned to 1 of 4 parallel groups: no pills, placebo pills (blinded), echinacea pills (blinded), or echinacea pills (unblinded, open-label). Echinacea groups received the equivalent of 10.2 g of dried echinacea root during the first 24 hours and 5.1 g during each of the next 4 days. Indistinguishable placebo tablets contained only inert ingredients.
  
  
  METHODS
  The primary outcome was the area under the curve for global severity, with severity assessed twice daily by self-report using the Wisconsin Upper Respiratory Symptom Survey, short version. Secondary outcomes included interleukin-8 levels and neutrophil counts from nasal wash, assessed at intake and 2 days later.
  
  
  RESULTS
  Of the 719 patients enrolled, 713 completed the protocol. Mean age was 33.7 years, 64% were female, and 88% were white. Mean global severity was 236 and 258 for the blinded and unblinded echinacea groups, respectively; 264 for the blinded placebo group; and 286 for the no-pill group. A comparison of the 2 blinded groups showed a 28-point trend (95% CI, -69 to 13 points) toward benefit for echinacea (P = 0.089). Mean illness duration in the blinded and unblinded echinacea groups was 6.34 and 6.76 days, respectively, compared with 6.87 days in the blinded placebo group and 7.03 days in the no-pill group. A comparison of the blinded groups showed a nonsignificant 0.53-day (CI, -1.25 to 0.19 days) benefit (P = 0.075). Median change in interleukin-8 levels and neutrophil counts were also not statistically significant (30 ng/L and 1 cell/high-power field [hpf] in the no-pill group, 39 ng/L and 1 cell/hpf in the blinded placebo group, 58 ng/L and 2 cells/hpf in the blinded echinacea group, and 70 ng/L and 1 cell/hpf in the open-label echinacea group).
  
  
  CONCLUSIONS
  Higher-than-expected variability limited power to detect small benefits.
  
  
  CONCLUSIONS
  Illness duration and severity were not statistically significant with echinacea compared with placebo. These results do not support the ability of this dose of the echinacea formulation to substantively change the course of the common cold.
  
  
  BACKGROUND
  National Center for Complementary and Alternative Medicine, National Institutes of Health.
authors.affiliation: Department of Family Medicine, University of Wisconsin, Madison, Wisconsin 53715, USA.
authors.forename: Bruce
authors.initials: B
authors.lastname: Barrett
authors.forename: Roger
authors.initials: R
authors.lastname: Brown
authors.forename: Dave
authors.initials: D
authors.lastname: Rakel
authors.forename: Marlon
authors.initials: M
authors.lastname: Mundt
authors.forename: Kerry
authors.initials: K
authors.lastname: Bone
authors.forename: Shari
authors.initials: S
authors.lastname: Barlow
authors.forename: Tola
authors.initials: T
authors.lastname: Ewers
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003139:Common Cold / Q000188:drug therapy* / Q000276:immunology; D020900:Echinacea / Q000009:adverse effects; D005260:Female; D006801:Humans; D016209:Interleukin-8 / Q000097:blood; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009504:Neutrophils; D010349:Patient Compliance; D010817:Physician-Patient Relations; D008517:Phytotherapy / Q000009:adverse effects; D015990:Placebo Effect; D010936:Plant Extracts / Q000009:adverse effects / Q000627:therapeutic use*; D011446:Prospective Studies; D012107:Research Design; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D016209:Interleukin-8; D010936:Plant Extracts