ver the last two decades, we have seen a tremendous increase in onsumer use of antioxidants and other micronutrient supplements for educing risk of disease prevention and ailments. There is therefore a rowing need to understand the characteristics, tissue uptake, metabolism, iochemical interactions, and the biological activities of various dietary icronutrients. A pertinent segment of research with an urgent need for ublic health nutrition guidelines is the authentication of the use of ntioxidant micronutrients in the prevention and treatment of many iseases, including cancer. Those micronutrients that are essential dietary factors cannot be syntheized in the human body or in other vertebrate animals. They are required nly in microor milligram quantities for the activity of a diverse array of iochemical pathways and metabolic processes in the body. They include itamins and trace elements, and a significant deficiency of these essential icronutrients in the body results in disease. The abundance or deficiency of ny given essential micronutrient in the body is determined by dietary intake nd by their utilization for different biological processes. It is difficult to evelop a complete directory of trace elements, as there is significant iversity in the types of diets consumed by different individuals. In this review, we will start with a brief discussion of antioxidant itamins and certain trace elements, which are involved in biological rocesses that have pathophysiologic implications in the gastrointestinal ystem. Then, we will discuss more extensively another class of microutrients, generally referred to as phytochemicals, which are also abunant in the diet, but are often left out of discussions of dietary icronutrients, presumably because direct evidence of reducing risk of arious oxidative-related diseases is just beginning to be realized.