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12 Accidental Medical Breakthroughs

Smallpox Vaccine

Edward Jenner was inspired to make the world’s first vaccine in 1796 when a milkmaid mentioned people who picked up cowpox, which caused sores but no lasting damage, didn’t get smallpox, which was deadly. So, Dr. Jenner injected a little boy with cowpox, waited until the disease passed, and then gave him smallpox, which never appeared. And lo, vaccines were born. 

Nitrous Oxide

Joseph Priestley used iron fillings to turn nitric acid into nitrous oxide, but until 1863, the anesthetic commonly known as “laughing gas,” was nothing more than a good time. Eventually doctors used it’s intoxicating effects to knock out patients and numb their mouths simply through inhalation. 


Karl Paul Link’s lucky visit from a farmer with hemorrhaging cows in 1933 led to the discovery of warfarin, a blood thinner . The cow’s hay had gone bad, infested by an anticoagulant named warfarin. It made a great rat poison until Link’s continued research discovered it would work to treat human blood clots, as opposed to just killing animals.


Viagra was supposed to help angina. Often mistaken for a heart attack, this condition causes the vessels bringing blood to the heart to constrict. The subjects didn’t notice much improvement in that aspect, but they did notice an exceptional amount of erections. Suddenly Viagra went from ordinary to extraordinary. It has become the most popular prescription of all time since its 1988 release.


The myth stands that a South American Indian desperate to cure his malaria-induced thirst drank from a pool surrounded cinchona trees, called “quina-quina” by locals. He was miraculously healed, and from there the bark turned from suspected poison to mosquito-borne illness’s cure. Jesuit missionaries take the official record, however, and are suspected to have learned of it from Peruvian tribes in the 1600s.


Two Danish pharmaceutical students were trying to create an anti-parasitic for the stomach, which they tested on themselves. Instead, the disulfiram they used made them incredibly sick when drinking at a party that evening. After they realized it prevented alcohol from being processed by the liver, they named it Antabuse and by 1951 it was one of the first effectual, medical methods of making alcohol less appealing to alcoholics. 



Two German doctors in 1889 were trying to figure out what the point of the pancreas was, so they took one out of a dog. After a few days, they realized flies were incredibly attracted to the dog’s urine. Testing showed sugar in its urine, which meant diabetes. And since the dog had been fine before, they decided they had caused it, thus finally connecting the dots. It took more than thirty years for a different pair of doctors to actually figure out what the pancreas produced, and Dr. Frederick G Banting and John J.R. McLeod were awarded a Nobel Prize for their work isolating and applying insulin.  

Pap Smears

In 1923, Dr. George Nicholas Papanicolaou switched from studying smears of guinea pig vaginal fluid to that of human women to see if the same changes happened during their period. By pure happenstance, one of his patients had uterine cancer, and the different cells were clear under his microscope. His namesake, the pap smear, became a regularly administered defense against gynecological cancer in women. 


Although Rune Elmqvist and Åke Senning intentionally invented the original implanted pacemaker, it only worked for three hours. While trying to create a heart beat recorder in 1958, Wilson Greatbatch accidentally put the wrong piece into his contraption. Instead, his creation beat out a pulse, and in 1960 it became a lifesaver that lasted for a year and a half, instead of an eighth of a day. 



Wilhelm Roentgen was a German physicist who accidentally "discovered" X-rays in 1895. While the existence of X-rays had been established earlier, Roentgen was the first to systematically study them. He stumbled upon them during his work with cathode rays—which are beams of electrons observed in a specialized tube. 


In the 1970s, Drs. Guinter Kahn and Paul Grant heard about a woman taking minoxidil for her blood pressure and growing hair where she shouldn’t be. They dabbled with the formula that belonged to the Upjohn Company and started rubbing it on their arms, only to find that hair actually started growing there. When they took their news to the company, Upjohn essentially snubbed them, reported them to the FDA, and filed their own patent. They ultimately got royalties, but no accreditation for finding a reversal for baldness. 

Cancer Cell Conversion

Scientists are still stumbling upon wonderful, accidental things. Just this year, researchers of acute lymphoblastic leukemia, a cancer that affects the cells that become white blood cells, were trying to keep the cancerous cells alive for their experiments. But what they did actually turned the cancerous cells into a white blood cell, making it not only no longer cancerous, but actually potentially effective against cancer. Things are looking good on mice, and the researchers are continuing their study in hopes of a viable treatment option.