A new boost has been given to selenium (Se) research by the identification of the close relationship between human nutrition or health and Se. Se is characterized by deficiency and dose-dependency. Se is toxic for human and crop when Se supplement goes a certain level. Organic Se has lower toxicity than inorganic Se. Furthermore, organic Se from plants has higher bioavailability and biological action than from animal and microorganism. Screening high Se containing plants and analyzing the component or chara...