# 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.

- **Patent:** US 644077
- **Original title:** Acetyl salicylic acid.
- **Owner:** FARBENFABRIKEN OF ELBERFELD Co
- **Granted:** 1900
- **Status:** Public domain (expired)
- **Times cited:** 6
- **Field:** pharmaceutical

## What it does

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 does NOT 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.

## Real-world examples

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

## 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.

## Frequently asked questions

### What does How Felix Hoffmann Invented Aspirin cover?

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

### Who owns patent US 644077?

FARBENFABRIKEN OF ELBERFELD Co owns this patent, granted in 1900.

### When does this patent expire?

This patent has expired and is now in the public domain — anyone can use the invention freely.

### What is patent US 644077 cited by?

This patent has been cited by 6 later patents that build on its ideas.

### What problem does this patent solve?

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.

### What does this patent NOT cover?

Does not cover the natural source of salicylic acid found in willow bark.

**Full plain-English explainer:** https://patentbrief.org/patent/us/644077/aspirin-acetylsalicylic-acid

**Original patent:** https://patents.google.com/patent/US644077

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


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