Organosulfur compounds have long been recognized as important antioxidants for the preservation of petroleum-derived products. It has also been suggested that the health benefits of garlic and related plant species can be ascribed to the radical-trapping antioxidant activity of some of their unique organosulfur constituents, such as allicin. This account highlights our efforts to elucidate the radical-trapping antioxidant mechanisms of allicin and related plant-derived organosulfur compounds as well as the organosulfur compounds used to preserve commercial and industrial products.