The role of Vitamin C in human nutritions has been the subject of longstanding debate. Primates (including humans) lost the ability to synthesize vitamin C about 60 million years ago and, as a consequence, … rely on dietary sources to counter the effect of this “genetic defect”. In contrast, other mammals (including common laboratory animal models such as the mouse and rat) synthesis large amounts of vitamin C to satisfy physiological needs. My lab has developed new tools for the ectopic expression of the murine Gulo gene to allow the controlled synthesis of vitamin C in cells and Gulo-deficient animals. I will describe the development and validation of these tools. I also will briefly review other animal models that have been developed for the study of dietary antioxidants.