🦠microbiology review

Pus

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Pus is a thick fluid composed of white blood cells, dead tissue, and bacteria, typically resulting from an infection. It is a sign of the body's immune response to fight off pathogens.

5 Must Know Facts For Your Next Test

  1. Pus formation is commonly associated with bacterial infections and can be found in abscesses or infected wounds.
  2. The primary components of pus include neutrophils, which are white blood cells that respond early during inflammation.
  3. Pus can vary in color from white to yellow, green, or brown depending on the type of infection and organisms involved.
  4. In skin and eye infections, pus discharge can indicate conditions like cellulitis or conjunctivitis.
  5. The presence of pus often triggers an inflammatory response, leading to redness, warmth, swelling, and pain in the affected area.

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