What does pus mainly consist of?

Pus mainly consists of dead white blood cells, particularly neutrophils, which have infiltrated an area of infection or inflammation. When the body responds to an infection, these immune cells are sent to the site to fight off pathogens. In the process of combating the infection, many of the white blood cells die, and the accumulation of these dead cells, along with remaining cellular debris and fluids, forms pus.

While pathogenic bacteria and live bacteria can be present in areas where pus is forming, they are not the primary constituent of pus itself. Pus is more of a reflection of the body’s response to infection rather than a collection of actively dividing or living bacteria. Damaged tissue can also be present alongside pus but again, it is not the main component. The dominant feature of pus is the presence of dead white blood cells, indicating that the body is undergoing an immune response to clear out infection or debris.