Pharmacy's Past: Chemist Discovers Aspirin and Heroin


Aspirin and heroin were discovered within weeks of each other in 1897 by Felix Hoffmann.

Did you know that both aspirin and heroin were created in a 2-week period in 1897, by German chemist Felix Hoffmann, who worked at Bayer? Ironically, aspirin is a very beneficial drug, while heroin is one of the most harmful, illegal substances. How did this happen?

Hoffmann was born in 1868, the son of a manufacturer in Swabia, Germany. Hoffmann worked in various local pharmacies before studying chemistry and pharmacy at the University of Munich, where we graduated in 1893.1

Hoffmann was recommended by 1 of his professors, Nobel Prize winner Adolf von Baeyer, and joined a newly established pharmaceutical research department at the Bayer Company. In the late 19th century, chemists worked on creating new substances that could be used as medication, rather than isolating active ingredients from natural products.1

Hoffmann spent the summer of 1897 adding the acetyl group to different molecules, hoping to improve the strength or decrease the toxicity of physiologically active substances.1 This strategy was known as 'acetylating' molecules, and was not new to Bayer. Phenacetin, a fever reducer, was created in 1888, and was an acetylated form of p-nitrophenol. Tannig, an antidiarrheal medication created in 1894, was acetylated tannic acid.1

Meanwhile, Heinrich Dreser, a professor, was working on the effect of codeine on breathing. He enlisted Hoffmann to acetylate morphine to produce codeine, but the result was a substance that was instead called heroin. The same compound, however, was already discovered in 1874 by an English chemist, so it could not be patented.1

Eventually, heroin was widely sold by Bayer and other companies to suppress cough, relieve pain of childbirth and serious war injuries, prepare patients for anesthesia, and control certain mental disorders. The addictiveness of heroin since recognized, it has been banned in most countries since the 1930’s.1

Years later, Hoffman would describe Bayer chemists as working by instinct and having a “good nose” for discovery.

According to legend, Hoffmann was in search of a medication to help his father, who was suffering from rheumatic pain. He acetylated salicylic acid, which was the active product in salves and teas made from willow bark and other plant materials. Willow bark had always been known for relieving pain and reducing fever, and in the early 19th century, chemists isolated salicylic acid from willow bark.1

Hoffmann went on to acetylate salicylic acid to produce acetylsalicylic acid. Heinrich Dreser, head of Bayer’s lab, tested the product on himself for toxicity, then tested on animals, then on humans in a hospital. This product was named aspirin. The A was for acetyl and the spirin was from Spirea, the genus name for the shrubs that were an alternative source of salicylic acid.

There is a debate still today, that another Bayer employee, Arthur Eichengrun, played a large role in the development of aspirin, but may have been left out of the story.

When Bayer applied for a patent, it was rejected. It turned out that acetylsalicylic acid had been synthesized at an earlier time, although not in a pure and stable form.

Chemist Hermann Kolbe had synthesized salicylic acid in 1859, after figuring out the chemical structure.1 Several years later, the Heyden Company began to manufacture and sell synthetic salicylic acid. This product was cheaper than the extract from willow bark itself, but had some adverse effects such as gastrointestinal irritation.

Regardless of the patent issue, Bayer knew it had a “potential blockbuster in aspirin,” and aggressively marketed the drug all over the world. In 1899, it was first launched under the trade name Aspirin™, initially as a powder supplied in glass bottles, and made the Bayer name world-famous.”2

Bayer was eventually able to obtain a patent in the United States, giving the company exclusivity on manufacturing from 1900 to 1917. In 1919, Bayer’s US plants were sold, and Sterling Products from West Virginia invested $3 million for these drug properties.1 Sterling was not able to protect aspirin's trademark status, and aspirin soon became a staple of the OTC market all over the world, as it remains today.

Sterling’s OTC business was eventually purchased by Smith Kline Beecham, who later sold the US portion, including aspirin, to Bayer for $1 billion.1

Hoffmann never married or had children, and retired in 1928. Remaining unknown and out of the public eye, he lived in Switzerland until he died, in 1946.2


  • Science History Institute. Felix Hoffmann. SHI website. Updated December 8, 2017. Accessed March 17, 2019
  • Bayer. Biographies: Felix Hoffmann. Bayer website. Updated April 30, 2018. Accessed March 17, 2019

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