Aspirin has been around for a very, very, long time. The ancient Egyptians and Greeks used extracts of the willow bark tree – which contains salicylic acid, aspirin’s active ingredient – as a remedy for pain and fever. Then in the 1800s, chemists figured out how to manufacture a concentrated version of this substance and market it as the pain reliever we call aspirin. Right up through the 1950s, aspirin remained the most popular medication for pain, fever reduction, and inflammation. But with the advent of better medications like acetaminophen (Tylenol) and ibuprofen (Advil), aspirin’s popularity began to wane. Thus the first act in aspirin’s long story came to a close.