Scottish surgeon Robert Liston developed a new kind of knife called the Liston knife in the mid-1800s to help him increase the speed of amputations – something very important in the days before anesthetics. In one operation, he accidentally amputated his assistant’s fingers along with his patient’s leg and nicked a spectator all in under three minutes. The spectator apparently died from fright on the spot, while the other two died of gangrene later on. It is the only surgery with a 300% mortality rate. In a different operation, he allegedly accidentally castrated his patient in his haste to finish the amputation.

This is a 1910 ad for “Mrs Winslow’s soothing syrup.” It featured 65mg of morphine per ounce, plus alcohol, and sold over 1.5 million bottles annually. It is believed to have been responsible for a huge number of infant mortalities.

12th century surgeons would treat hemorrhoids by burning them away with hot irons. Maybe not deadly, but pretty painful.

Walter Freeman developed his now infamous “lobotomy” to treat all sorts of miscellaneous mental symptoms in 1936. He performed it on almost 3,500 people, leaving 15% dead, and many more permanently severely disabled.

In the 1920s, Austrian physician Julius Wagner-Jauregg concluded that syphilis was treatable by inducing high fevers… with malaria. Giving patients malaria proved to be a predictably fatal choice. He won the Nobel prize for his efforts.

From the 1500s all the way to the 1900s, doctors believed that a leading cause of infant mortality was connected to babies’ teeth coming in. (Correlation does not equal causation.) As a result, they did everything from cutting teeth, to putting leeches on gums. One popular technique was called “gum lancing,” which cut gums down to the bone. Many children died from resulting infections.

Trepanning was the practice of drilling large holes in people’s skulls to alleviate migraines or other bad headaches. Yes, many people died.

Arsenic is well known as a fatal poison. However, it was used to treat fevers, headaches and other miscellaneous conditions for hundreds of years.