4 great medical discoveries that were purely accidental

Ross Chainey
Content Lead, UpLink, World Economic Forum
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Scientists may have made a giant leap forward in the treatment of cancer – by accident.

A team of Danish researchers, looking for a way to protect pregnant women against malaria, found that proteins in the malaria parasite can attack cancer cells. The discovery is a potential game-changer in the hunt for a cure for cancer.

The scientists from the University of Copenhagen found that malaria proteins, armed with a toxin, sought out and absorbed cancer cells, released the toxin and then destroyed the cells. The tests were carried out on mice, but the team plans to start testing on humans within four years.

“For decades, scientists have been searching for similarities between the growth of a placenta and a tumor,” Ali Salanti, a professor in the department of immunology and microbiology at the University of Copenhagen, said in a press release. “The placenta is an organ, which within a few months grows from only few cells into an organ weighing [approximately] 2 pounds, and it provides the embryo with oxygen and nourishment in a relatively foreign environment. In a manner of speaking, tumors do much the same – they grow aggressively in a relatively foreign environment.”

If the discovery lives up to its promise, it wouldn’t be the first time a monumental medicinal discovery was made by accident. Here are four more.

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On returning to his lab after a month-long holiday in 1928, Scottish doctor Alexander Fleming discovered that a culture of the bacteria staphylococcus aureus, which he had been experimenting with, had been destroyed by a mould growing in his petri dishes. Fleming had discovered the first antibiotic, which he called penicillin. The drug has saved countless lives and Alexander Fleming was awarded the Nobel Prize for medicine in 1945.

The implantable pacemaker

Wilson Greatbatch invented the implantable pacemaker – but he didn’t mean to. The American engineer, a lifelong inventor, was attempting to build a device that recorded heart rhythms, but after he mis-assembled the contraption, he noticed that it was giving off a heartbeat-like pulse. Greatbatch realized that this could be used as a pacemaker, only a much smaller one than previous models. After two years of refinements, his design was patented in 1960 and soon went into production.


The blood-thinner, or anticoagulant, was discovered in the 1930s by American biochemist Karl Paul Link. The scientist was approached by a Wisconsin farmer whose cattle were experiencing unexplained haemorrhages. Examining the cattle’s feed, Link discovered that it contained the anticoagulant substance. Link was able to isolate a compound in what is now known as warfarin that could treat patients suffering from blood clots, and it’s still in use today.

Nitrous oxide

Nitrous oxide, or laughing gas as it’s often called, was discovered in 1772 by English clergyman and scientist Joseph Priestly (the man who also the first to isolate oxygen, carbon monoxide and carbon dioxide). Priestly found that putting iron fillings into nitric acid released the gas, which had anti-panic properties. But it wasn’t until the 1840s when forward-thinking doctors and dentists began experimenting with it as a tranquilizer. In between, it had mainly been used as a mood enhancer at parties, and had gained a reputation as something of a recreational drug.

Have you read?
4 big breakthroughs we expect by 2030
How will the Nobel scientists transform medicine?
Why curiosity is key to medical breakthroughs

Author: Ross Chainey, Digital Media Specialist, World Economic Forum

Image: A scientist prepares protein samples for analysis in a lab at the Institute of Cancer Research in Sutton, July 15, 2013. REUTERS/Stefan Wermuth

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