When antimatter comes into contact with matter it annihilates: the mass of the particle and its antiparticle are converted into pure energy. Large-scale annihilation of antimatter and matter could theoretically be used in a destructive way.

However, there is no way that antimatter could be created in sufficient quantities to be used in a bomb. Nor could it be transported, as the antimatter traps capable of containing any significant quantity of antimatter would have to be enormous, and would require huge amounts of energy to operate.