STOP A COLD IN 3 HOURS??
Yes - it's true. From Prevention's Book Healing with Vitamins
Take 2,000 mgs of Vitamin C an hour for 3 hours the first sign of cold symptoms. Usually the cold is gone by then. (Writer's note: I never got past the second hour). If it's still not gone, take 1,000 mgs an hour until it is.
Note of caution: Daily doses of Vitamin C larger than 1,200 mgs can cause diarrhea in some people so experiment with the dose that's right for you.