The yellowish substance that builds up around an injury in the process of inflammation is?

The yellowish substance that builds up around an injury in the process of inflammation is pus. Pus is a thick, creamy fluid that is made up of dead white blood cells, bacteria, and other debris. It is produced when the body's immune system fights off an infection. Pus can be a sign of a bacterial infection, and it is important to see a doctor if you have pus draining from a wound.