For a long period, Selenium was considered mainly a toxic element and has been the object of disputes for its controversial balance between beneficial and toxic effects. Nowadays, many evidences demonstrated its role as essential microelement in mammalian diet, having an essential role in redox homeostasis of all the living systems. Around 25 proteins were discovered to contain a selenocysteine in the place of the more common sulfureted amino acid and, in this protein, selenium have the main role in the catalytic center and playng a key role in several major metabolic pathways such as thyroid hormone metabolism, antioxidant defense systems, and immune functions. Many studies report that selenium has a protective effect against some forms of cancer decreases, cardiovascular disease mortality, regulates the inflammatory mediators in asthma, maintains bone homeostasis and protects against bone loss. Antioxidant activities of organoselenium compounds has been widely studied and discussed in a number of recent review article. In this communication taking inspiration from a number of recent publications we want to highlight that other biological activities can be envisioned for organoselenium compounds deriving from the peculiar reactivity of this element.