In 1928 Alexander Fleming (above) was investigating influenza – a major killer of the day (recall the Spanish Flu epidemic of 1918-19 killed ten times more people than WWI). A speck of dust contaminated one of his petri dishes of staphylococcus. Around the resulting patch of mould, Fleming discovered a clear, bacteria-free zone – later identified as containing the world-changing antibiotic penicillin. He was later awarded a knighthood and a Nobel Prize.


The Birth Control Pill

The Birth Control Pill © Getty Images
© Getty Images

In the quest to produce a safe and reliable prophylactic, scientists in the 1950s tested pills containing synthetic progesterone on women in Puerto Rico. When removal of “impurities” from the pills worsened (and not improved) study results, chemists realized that the “impurity” was actually oestrogen – and that a pill combining the two hormones was the chemical key.

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Chloral hydrate

Oscar Liebreich (© J. Baruch/ullstein bild via Getty Images)
Oscar Liebreich © J. Baruch/ullstein bild via Getty Images

The sedative properties of the world’s first mass-produced synthetic hypnotic were discovered thanks to an incorrect but fruitful hunch. In 1869 German pharmacologist Oscar Liebreich believed that the chemical would be converted into chloroform in the body, inducing sleep. Chloral hydrate itself however can send patients under, and thus the world’s first sleeping pill hit the scene.



© iStock
© iStock

One of the world’s first anti-depressants was first synthesized in 1951, and used initially to treat tuberculosis. When clinicians found that some patients exhibited euphoria and hyperactive behaviour under the drug’s influence, they revealed that it is a “monoamine oxidase inhibitor” – meaning it prevents the breakdown of monoamines, such as 5-HT, also known as serotonin.

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Albert Hofmann (© VIRGINIA/ullstein bild via Getty Images)
Albert Hofmann © VIRGINIA/ullstein bild via Getty Images

When Swiss chemist Albert Hoffman was tinkering in the lab developing drugs to treat post-partum hemorrhaging his fingers touched a bit of LSD-25 and the world began to shimmer: “I perceived an uninterrupted stream of fantastic pictures, extraordinary shapes with intense kaleidoscopic play of colours,” he wrote in his diary. On 19 April 1943, a day known as ‘Bicycle Day’, he decided to experiment with 0.25mg of the drug before riding home by bicycle. The world melted, and the psychedelic drug was discovered.



Blister packs containing Viagra tablets (© Simon Dawson/Bloomberg via Getty Images)
Blister packs containing Viagra tablets © Simon Dawson/Bloomberg via Getty Images

Monkey testicle implants, tiger penis soup, constrictive rings and pneumatic devices have all been deployed in the battle against impotence. But it was not until researchers accidentally discovered that sildenafil citrate, a drug developed at a treatment for jet jag, had impacts below the belt. Why? The drug dilates by relaxing muscles, allowing blood to flow into the penis.


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Zoe Cormier is a science writer, broadcaster and public speaker with a BSc in zoology from the University of Toronto. She is the author of Sex, Drugs and Rock n’ Roll: The Science of Hedonism and the Hedonism of Science and her work has appeared in Nature, The Guardian and The Times.