The significance of the evidence about ascorbic acid and the common cold

Proc Natl Acad Sci U S A. 1971 Nov;68(11):2678-81. doi: 10.1073/pnas.68.11.2678.


Only four independent double-blind studies have been reported of the effect of ascorbic acid regularly ingested in daily amounts more than 100 mg, in comparison with a placebo, in decreasing the incidence and integrated morbidity of the common cold for subjects exposed to cold viruses in the ordinary way and without colds when the test period began. A statistical analysis of these four studies leads to rejection of the null hypothesis that ascorbic acid has no more protective power than the placebo at the 99.86% level of confidence for the incidence of colds and the 99.9978% level of confidence for the integrated morbidity.

Publication types

  • Clinical Trial
  • Review

MeSH terms

  • Administration, Oral
  • Ascorbic Acid / therapeutic use*
  • Clinical Trials as Topic
  • Common Cold / prevention & control*
  • Female
  • Humans
  • Male
  • Placebos
  • Statistics as Topic
  • Time Factors


  • Placebos
  • Ascorbic Acid