Within the framework of the health-effects based interpretation of the principle prohibiting superfluous injury or unnecessary suffering (SIrUS), Chap. 4 presents a comprehensive review of selected controversial weapons and their impacts on human health. The chapter focuses on contentious weapons such as nuclear arms, antipersonnel landmines, incendiaries, and chemical agents, and it evaluates the immediate and long-term health impacts that these weapons have on survivors. This chapter highlights the human cost connected with chemical and nuclear weapons by drawing on field research, which includes interviews with victims of chemical weapons and other communities that these weapons have affected. It is a legal paradox that chemical weapons enjoy global ban due to their abhorrent effects while nuclear weapons remain allegedly lawful. This chapter thus illustrates how such health-related consequences undermine the traditional military-centric understanding of SIrUS by offering medical facts on the inflicted suffering and long-term injuries. It also suggests that contemporary legal frameworks are increasingly considering health-based factors when deciding the legality of specific weapons.