Aspirin is a common medicine that reduces pain, fever, and swelling. When you have a headache, fever, or sore muscles, aspirin helps by blocking chemicals in your body that signal pain and cause inflammation.

Invented in 1897 by a German chemist named Felix Hoffmann, aspirin became one of the world's most widely used medicines. Hoffmann was trying to help his father, who suffered from arthritis pain. The active ingredient in aspirin, called acetylsalicylic acid, comes from a natural substance found in willow tree bark that people had used to treat pain for thousands of years.

Today, doctors also prescribe aspirin to help prevent heart attacks and strokes in some patients because it prevents blood from clotting too easily. However, aspirin isn't safe for everyone: children and teenagers shouldn't take it for fevers or viral infections because of a rare but serious condition called Reye syndrome.

When something becomes as well known and useful as aspirin, we sometimes call it a household name, meaning nearly every family keeps it in their medicine cabinet.