A person can take too much vitamin C under certain circumstances. Vitamin C is water soluble, which means that the body flushes out the vitamin C it doesn't need; however, people who take megadoses of vitamin C can experience unpleasant symptoms of toxicity.
The symptoms of vitamin C toxicity can include diarrhea, nausea and vomiting, bloating, cramps, insomnia, heartburn and headache. Some people also develop kidney stones from too much vitamin C.
Nutritionists recommend that people get between 65 and 90 milligrams of vitamin C a day but advises against consuming more than 2,000 milligrams per day. Vitamin C is an antioxidant that protects the body from free radical damage.