Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) used to reduce pain, inflammation, and fever. It is commonly taken for headaches, toothache, muscle pain, joint pain, menstrual cramps, and swelling due to injury or arthritis. Ibuprofen works by blocking substances in the body called prostaglandins that cause pain, swelling, and fever. It is effective for mild to moderate pain but should be taken after food, as it can sometimes cause stomach irritation. It should be used carefully and as advised, especially in people with stomach, kidney, or heart problems.