To anyone that forgets it, the irradiated head of Alexander Litvinenko is an eternal reminder: woe to anyone who defies the House of Russia. Masters in the art of using poison, Russians have made it a key weapon in their strategic arsenal. Over the past twenty years, several high-profile cases have made their mark. What goes on behind the scenes as they take shape sheds light on the relationship between the Kremlin and the West. Behind each of these cases, there is a tug of war, with major diplomatic and geostrategic issues. Struggles for influence, attacks on the integrity of the empire and its energy resources, each poisoning reveals the underside of a formidable game of chess in the line of the Cold War, and lays the foundations of what has been played out since the beginning of the conflict with Ukraine. To retrace this history, four cases deserve to be explored, each with different methods, stakes and power relations, but which give the whole a curious coherence.