A painkiller is a medicine that reduces or stops pain. When you have a headache, a fever, or a sore throat, taking a painkiller can help you feel better. Common painkillers include aspirin, ibuprofen, and acetaminophen (which you might know by the brand name Tylenol).

Painkillers work by blocking or changing the signals your body sends to your brain that say “this hurts!” Some painkillers also reduce inflammation, which is the swelling and redness that happens when you injure yourself. If you've ever scraped your knee badly or sprained your ankle, a painkiller can help with both the pain and the puffiness.

Doctors sometimes prescribe stronger painkillers for serious injuries or after surgery. These medications need to be used carefully and exactly as directed, because they're powerful tools. The right painkiller at the right time can help someone heal more comfortably, but they should always be taken under adult supervision and never shared with others.

The word painkiller is also sometimes used metaphorically. If someone says music is their painkiller, they mean it helps them feel better emotionally, though it doesn't actually stop physical pain the way medicine does.