Since about 200 B.C., willow tree bark has been chewed to relieve aches and pains.
The active element is salicylic acid, which reduces pain and fever.
In the 1890s, Felix Hoffman, an employee of Bayer & Company, figured out how to dilute the acid, and the Bayer Company began selling it under the brand name Aspirin.
The name was a derivative of the Latin name for another good source of salicylic acid, the plant called queen of the meadow.
Today most asprin is synthetic.
Aspirin has an antiplatelet effect, and is often recommended to help prevent heart attacks, strokes, and blood clots in people with a high risk of developing blood clots.
Aspirin may also be given immediately after a heart attack to reduce the risk of a recurrence.
Some side effects of aspirin include gastrointestinal ulcers, stomach bleeding, and tinnitus, especially in higher doses.