One day, my next door neighbor came to my door and said her 5-year-old had scarfed down half a bottle of vitamin C chewables. She wondered, naturally, if there was danger. I asked if the child was showing any symptoms. She thought for a moment, and replied, “Well, his asthma went away.” For asthma, Robert Cathcart, MD, recommended a daily vitamin C dosage of between 15,000 to 50,000 milligrams (mg), divided into eight doses. The doctor reported that he had seen this work again and again. Read more.