Inflammation is your body's natural response to harmful stimulants, damaged cells, irritants, infection, and injury: it's an attempt to stop the damage, protect your cells, remove the harmful stimuli, and start the healing process. When you get a cut or other injury, you can see inflammation in action. When an injury happens, your body releases chemicals and white blood cells into your bloodstream, ready to attack and kill invading bacteria, viruses, fungi, and other microbial invaders. The redness and swelling around the wound shows that your blood vessels are expanding, bringing in white blood cells and antibodies to fight the infection, along with proteins and other nutrients to repair the damage.
"Inflammation" is from the Latin word inflammatio, which means to set on fire, and warmth, along with swelling and pain, is a feature of inflammation.
Without inflammation, your wounds and infections will not heal. So inflammation is beneficial, or even essential, up to a point. All that swelling and repair work can be painful (which is why anti-inflammatory medicines, such as ibuprofen, are effective painkillers). Unfortunately, although anti-inflammatory drugs can suppress symptoms temporarily, they don't cure the underlying problem. And prolonged or chronic inflammation can lead to diseases. Chronic inflammation is now recognized as a type of non-specific immune response.