Ibuprofen and paracetamol (also known as acetaminophen) are two of the most commonly used over-the-counter medicines to treat pain and fever. They do have different mechanisms of action.
Paracetamol reduces the pain signals to the brain and also prevents the release of pain-causing chemicals (prostaglandins) that produce pain and fever.
Ibuprofen works differently. It blocks the body's production of these pain-causing chemicals (prostaglandins) to reduce pain and fever. Ibuprofen also helps reduce inflammation.