1Detection
Resident immune cells recognize microbes or signals released by damaged tissue.
Inflammation
A natural defense with a delicate balance
Inflammation is the body’s coordinated response to infection, injury and other harmful conditions. It helps recruit immune cells, remove threats and begin repair. When responses are excessive, misdirected or persistent, they can damage tissues and contribute to disease.
Explore inflammation →What Is Inflammation?
Inflammation is a coordinated response involving innate and adaptive immune cells, blood vessels and tissue cells. Microbial signals or tissue injury trigger mediators that change blood flow, vascular permeability and leukocyte movement.
Its purpose is to contain a threat, clear harmful material and support recovery. The response must also be controlled and resolved.
Learn the basics →The Inflammatory Response in Action
Five connected processes help move a local response toward recovery.
2Activation
Cytokines, chemokines and other mediators coordinate local responses.
3Recruitment
Vascular changes and adhesion signals bring leukocytes into the affected tissue.
4Elimination
Immune cells and proteins help remove microbes, debris and damaged cells.
5Resolution
Active stop signals, cellular cleanup and repair help restore tissue function.
Signs of Inflammation
Classic local signs include redness, warmth, swelling, pain and loss of function. They reflect changes in blood flow, fluid movement and tissue signaling. Not every inflammatory process causes all five visible signs.
Beneficial Effects of Inflammation
An appropriately regulated response supports protection and recovery.
Helps eliminate viruses, bacteria and other microbes.
Removes dead cells and tissue debris.
Creates signals and conditions that support tissue restoration.
When Inflammation Goes Wrong
Excessive, misdirected or persistent inflammation can damage healthy tissue. Chronic inflammatory processes contribute to many diseases, alongside other genetic, environmental and metabolic factors. Inflammation is not the sole cause of every condition shown here.
Inflammation and Aging
Persistent low-grade inflammation is often called inflammaging. It is associated with aging and several age-related diseases, but varies greatly between people. Changes in immune regulation, tissue damage and resolution pathways all contribute.
Explore inflammaging →Everyday Choices for a Healthier Balance
A balanced dietary pattern, regular physical activity, adequate sleep, stress management and avoiding tobacco support overall health and can influence inflammatory processes. Their effects vary; the goal is healthy regulation, not eliminating inflammation.
Science today.
Healthier tomorrows.
Understanding inflammation helps you understand defense, repair and long-term health.
Explore more topics →Selected sources and references
- Origin and physiological roles of inflammation
- Chronic inflammation across the lifespan
- Resolution of inflammation: definitions and mechanisms
- Aging and the resolution of inflammation
- Dietary patterns and inflammatory biomarkers
- Sleep and inflammation
Artwork illustrates the main mechanisms schematically; molecular sizes, colors and distances are not literal.