This book provides evidence of vitamin C supplementation in the treatment and prevention of important human diseases, such as pre-eclampsia, hypertension, atherosclerosis, diabetes, among others. In addition, although this antioxidant vitamin is well tolerated, related studies are included which detail its side effects, such as kidney stones formation, diarrhoea and indigestion. The underlying mechanisms accounting for these undesirable effects remain to be determined, whereas the prevailing viewpoints consider vitamin C as a safety supplement.