Vitamin C has been shown to not have a toxicity level up to 10,000 milligrams (10 grams) per Linus Paulings' previous studies. High doses of vitamin C can cause stomach irritation if taken orally via pills or powders. Some advanced forms of vitamin C have been able to avoid this with various encapsulation methods. As for the story you are referring to, it sounds like Allan Smith, the farmer from New Zealand. Got Swine Flu in Fiji, was nearing death and was going to be taken off of life support. His family decided high dose vitamin C couldn't hurt therefore they administered 100 grams (100,000 milligrams!) at a time. After a few months he was back home. Truly a miracle.