title: Efficacy of an extract of North American ginseng containing poly-furanosyl-pyranosyl-saccharides for preventing upper respiratory tract infections: a randomized controlled trial.
abstract: BACKGROUND
  Upper respiratory tract infections are a major source of morbidity throughout the world. Extracts of the root of North American ginseng (Panax quinquefolium) have been found to have the potential to modulate both natural and acquired immune responses. We sought to examine the efficacy of an extract of North American ginseng root in preventing colds.
  
  
  METHODS
  We conducted a randomized, double-blind, placebo-controlled study at the onset of the influenza season. A total of 323 subjects 18-65 years of age with a history of at least 2 colds in the previous year were recruited from the general population in Edmonton, Alberta. The participants were instructed to take 2 capsules per day of either the North American ginseng extract or a placebo for a period of 4 months. The primary outcome measure was the number of Jackson-verified colds. Secondary variables measured included symptom severity, total number of days of symptoms and duration of all colds. Cold symptoms were scored by subjects using a 4-point scale.
  
  
  RESULTS
  Subjects who did not start treatment were excluded from the analysis (23 in the ginseng group and 21 in the placebo group), leaving 130 in the ginseng group and 149 in the placebo group. The mean number of colds per person was lower in the ginseng group than in the placebo group (0.68 [standard deviation (SD) 0.82] v. 0.93 [SD 0.91], difference 0.25%, 95% confidence interval [CI] 0.04-0.45). The proportion of subjects with 2 or more Jackson-verified colds during the 4-month period (10.0% v. 22.8%, 12.8% difference, 95% CI 4.3-21.3) was significantly lower in the ginseng group than in the placebo group, as were the total symptom score (77.5 [SD 84.6] v. 112.3 [SD 102.5], difference 1.5%, 95% CI 1.2-2.0) and the total number of days cold symptoms were reported (10.8 [SD 9.7] v. 16.5 [SD 13.8] days, difference 1.6%, 95% CI 1.3-2.0) for all colds.
  
  
  CONCLUSIONS
  Ingestion of a poly-furanosyl-pyranosyl-saccharide-rich extract of the roots of North American ginseng in a moderate dose over 4 months reduced the mean number of colds per person, the proportion of subjects who experienced 2 or more colds, the severity of symptoms and the number of days cold symptoms were reported.
authors.affiliation: Capital Health, Edmonton, Alta.
authors.forename: Gerald N
authors.initials: GN
authors.lastname: Predy
authors.forename: Vinti
authors.initials: V
authors.lastname: Goel
authors.forename: Ray
authors.initials: R
authors.lastname: Lovlin
authors.forename: Allan
authors.initials: A
authors.lastname: Donner
authors.forename: Larry
authors.initials: L
authors.lastname: Stitt
authors.forename: Tapan K
authors.initials: TK
authors.lastname: Basu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003139:Common Cold / Q000473:pathology / Q000517:prevention & control*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D005894:Panax / Q000737:chemistry*; D008517:Phytotherapy; D010936:Plant Extracts / Q000627:therapeutic use; D018517:Plant Roots / Q000502:physiology; D011134:Polysaccharides / Q000627:therapeutic use*; D012720:Severity of Illness Index
chemical_list: D010936:Plant Extracts; D011134:Polysaccharides