Vitamin C is an essential nutrient, well known for its use in preventing scurvy and treating autoimmune illnesses and infections. Vitamin C has a long and controversial history with respect to its potential use as an anti-cancer agent. At present, vitamin C is classified as a complementary/alternative treatment for cancer. Recently, in vitro and animal studies discovered that high dose intravenous vitamin C acts as a pro-drug, selectively killing cancer cells. This literature review aims to analyse the latest research into the effectiveness of high dose intravenous vitamin C in the treatment of cancer.