Mega-dose vitamin C in treatment of the common cold: a randomised controlled trial.
OBJECTIVE
To determine the effect of large doses of vitamin C in the treatment of the common cold.


METHODS
Double-blind, randomised clinical trial with four intervention arms: vitamin C at daily doses of 0.03g ("placebo"), 1 g, 3g, or 3g with additives ("Bio-C") taken at onset of a cold and for the following two days.


METHODS
400 healthy volunteers were recruited from staff and students of the Australian National University, Canberra, ACT, between May 1998 and November 1999. The trial continued for 18 months.


METHODS
Participants were instructed to commence medication when they had experienced early symptoms of a cold for four hours, and to record daily their symptoms, severity, doctor visits and use of other medications.


METHODS
Duration of symptoms and cold episodes; cumulative symptom severity scores after 7, 14 and 28 days; doctor visits; and whether participants guessed which medication they were taking.


RESULTS
149 participants returned records for 184 cold episodes. No significant differences were observed in any measure of cold duration or severity between the four medication groups. Although differences were not significant, the placebo group had the shortest duration of nasal, systemic and overall symptoms, and the lowest mean severity score at 14 days, and the second lowest at 7 and 28 days.


CONCLUSIONS
Doses of vitamin C in excess of 1 g daily taken shortly after onset of a cold did not reduce the duration or severity of cold symptoms in healthy adult volunteers when compared with a vitamin C dose less than the minimum recommended daily intake.
Audera
C
C
National Centre for Epidemiology and Population Health, Australian National University, Canberra, ACT.
Patulny
R V
RV
Sander
B H
BH
Douglas
R M
RM
D000328:Adult; D000704:Analysis of Variance; D001205:Ascorbic Acid / Q000008:administration & dosage*; D001315:Australia; D003139:Common Cold / Q000188:drug therapy* / Q000517:prevention & control; D016001:Confidence Intervals; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012720:Severity of Illness Index; D016896:Treatment Outcome
D001205:Ascorbic Acid