An anti-inflammatory is a medicine that calms inflammation: the hot, red, painful swelling that happens when a part of the body is hurt or is fighting an illness. As an adjective it describes the medicine or the cream (an anti-inflammatory gel); as a noun it is the medicine itself (she took an anti-inflammatory). Doctors reach for this word when the problem is not only pain, but swelling — a twisted ankle, a sore joint, a rash that puffs up. Though actually, in ordinary talk people often say painkiller for any pill that makes them feel better, and that hides a real split: some medicines only cover the pain and the fever, while an anti-inflammatory tries to quiet the swelling too. You will hear it in clinics and on packets; it is a careful, slightly formal word, not a playground one. Some anti-inflammatories are mild enough to buy at a pharmacy; some are strong steroid medicines a doctor must watch. People also stretch it a little: an anti-inflammatory diet is a popular, looser way of saying food that may help with swelling, which is a hope more than a promise.