How Felix Hoffmann Invented Aspirin

The 1900 patent for acetylsalicylic acid, the chemical compound that became the world's most common pain reliever, known as Aspirin.

What it covers

This patent describes the chemical process for creating acetylsalicylic acid. It involves reacting salicylic acid with acetic anhydride to produce a stable, usable form of the drug. By acetylating the salicylic acid, the inventor created a compound that was significantly less irritating to the stomach than the raw salicylic acid used previously for pain and inflammation.

What it doesn't cover

• —Does not cover the natural source of salicylic acid found in willow bark.
• —Does not cover other non-acetylated derivatives of salicylic acid.
• —Does not cover the specific brand name Aspirin, which was a trademarked term.

The clever bit

The innovation was in the acetylation process, which successfully stabilized the compound for human consumption without the severe stomach side effects common to earlier treatments.

Why it matters

This patent marks the birth of the modern pharmaceutical industry. It transformed how society manages pain, fever, and inflammation, moving medicine from herbal extracts to standardized, mass-produced synthetic chemicals.

Real-world examples

• 1.Bayer Aspirin
• 2.Generic acetylsalicylic acid tablets
• 3.Low-dose aspirin for cardiovascular health