Efficacy of COLD-fX in the prevention of respiratory symptoms in community-dwelling adults: a randomized, double-blinded, placebo controlled trial

J Altern Complement Med. 2006 Mar;12(2):153-7. doi: 10.1089/acm.2006.12.153.


Background: COLD-fX (CVT-E002), a proprietary extract of the roots of North American ginseng (Panax quinquefolium), rich in poly-furanosyl-pyranosyl-saccharides, has been found efficacious in the prevention of respiratory infections in institutionalized seniors and healthy adults.

Objective: We examined the efficacy of COLD-fX in the prevention of acute respiratory illness (ARI) in community dwelling seniors.

Design: This was a randomized, double-blind, placebo controlled trial.

Intervention: The participants were asked to take 2 capsules/day of either COLD-fX or placebo (200 mg/ capsule) for a period of 4 months.

Subjects: A total of 43 community-dwelling adults aged 65 years or older were recruited. Following one month of intervention, subjects were immunized with influenza vaccine.

Outcome measures: Subjects recorded the incidence and duration of respiratory symptoms during the study. They also recorded the incidence of adverse events during the study.

Results: The frequency and duration of ARI during the first two months of the study was found to be similar in the two groups. However, during the last 2 months (November and December) significantly fewer subjects in the COLD-fX group 32% reported ARI compared to the placebo group 62%. The duration of symptoms during the last 2 months was significantly shorter in the COLD-fX group than the placebo group (5.6 days in the COLD-fX group vs 12.6 days in the placebo group). There was no influenza illness circulating in the community during the period of the study.

Conclusions: Ingestion of COLD-fX by immunocompetent seniors during an early "cold and flu" season reduced the relative risk and duration of respiratory symptoms by 48% and 55%, respectively. Daily COLD-fX administration can thus be a safe, natural therapeutic means for the prevention of ARI in healthy seniors.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Common Cold / drug therapy
  • Common Cold / prevention & control*
  • Double-Blind Method
  • Female
  • Humans
  • Influenza Vaccines / administration & dosage
  • Influenza, Human / drug therapy
  • Influenza, Human / prevention & control*
  • Male
  • Panax*
  • Phytotherapy / methods*
  • Plant Extracts / therapeutic use*
  • Plant Roots*
  • Treatment Outcome


  • COLD-fX
  • Influenza Vaccines
  • Plant Extracts