Medicine & Health
How does inflammation work?
Inflammation is the body's defensive response to injury or infection. The immune system rushes blood, fluid, and white blood cells to the affected area to fight invaders and start repair — causing the familiar redness, heat, swelling, and pain.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how inflammation works.
Step by step
- 1It's triggered by injury, infection, or irritants the body needs to deal with.
- 2Blood vessels widen and become leaky, bringing immune cells and fluid to the site.
- 3This causes the classic signs: redness, heat, swelling, and pain.
- 4White blood cells destroy invaders and clear damaged tissue so healing can begin.
- 5Short-term it's protective; chronic (long-term) inflammation can harm healthy tissue.
Frequently asked questions
- Why does inflammation cause redness and swelling?
- Blood vessels widen and leak fluid to bring immune cells to the area — more blood causes the redness and heat, and the leaked fluid causes the swelling.
- Is inflammation good or bad?
- Short-term (acute) inflammation is essential for fighting infection and healing. But chronic, long-lasting inflammation can damage healthy tissue and is linked to many diseases.
- What's the difference between acute and chronic inflammation?
- Acute inflammation is a fast, short-term response to injury or infection; chronic inflammation is a prolonged, low-grade response that can persist for months or years and harm the body.