High dose vitamin C may be useful to to your body in many ways. Vitamin C is an antioxidant and will scavenge free radicals. At high doses, it can help balance your oxidative stress in situations of chronic illness, chronic fatigue, or recovering your body from an injury or surgery. It is also helpful for post burn management or severe sun damage.
High dose vitamin C has been use as a anti-cancer treatment adjunct. It may also also help reduce the side effects of other conventional cancer treatment such as chemotherapy and radiation therapy like fatigue, nausea and vomiting.