What are you thinking about here? If it is "matter/antimatter" "particles/antiparticles" then this is not true. There are still conserved quantities in annihila

What are you thinking about here? If it is "matter/antimatter" "particles/antiparticles" then this is not true. There are still conserved quantities in annihilation of particles and antiparticles which makes other particles and/or energy come out of these annihilations.