Too much vitamin C can be bad for people, according to WebMD. Overdosing on vitamin C can lead to stomach cramps, nausea and diarrhea. It commonly results from taking too many supplements.
The National Health Service in the United Kingdom says that the symptoms of vitamin C overdose should stop once a person goes off these supplements. Vitamin C is water soluble, and the body cannot store it. The kidneys flush it out quickly. The National Health service says that a person's regular diet should provide enough vitamin C (about 40 milligrams) and recommends absolutely no more than 1,000 milligrams daily.