Does Vitamin C prevent and treat the common cold?

From: The Cochrane Collaboration

Journal rating:
rating: 98%
Study Quality:
rating: 40%

Overall Reliability

Article Quality:
rating: 50%
rating: 75%


  • 29 trials involving 11,306 participants


  • The paper is a systematic review / meta-analysis of all relevant trials.
  • A search of the literature to discover whether oral doses of 0.2 g per day or more of vitamin C reduce the incidence, duration or severity of the common cold when used regularly every day or as therapy after onset of symptoms.


  • Regular ingestion of vitamin C had no effect on common cold incidence in the ordinary population.
  • However, it had a modest but consistent effect in reducing the duration and severity of common cold symptoms.


  • No (without confidence)


Editors Notes

  • One large trial with adults reported equivocal benefit from an 8g therapeutic dose at the onset of symptoms, and two trials using five-day supplementation reported benefit.