1. Bloodletting

For thousands of years, medical practitioners clung to the belief that sickness was merely the result of a little “bad blood.” Bloodletting probably began with the ancient Sumerians and Egyptians, but it didn’t become common practice until the time of classical Greece and Rome. Influential physicians like Hippocrates and Galen maintained that the human body was filled with four basic substances, or “humors”—yellow bile, black bile, phlegm and blood—and these needed to be kept in balance to maintain proper health. With this in mind, patients with a fever or other ailment were often diagnosed with an overabundance of blood. To restore bodily harmony, their doctor would simply cut open a vein and drain some of their vital fluids into a receptacle. In some cases, leeches were even used to suck the blood directly from the skin.

While it could easily result in accidental death from blood loss, phlebotomy endured as a common medical practice well into the 19th century. Medieval doctors prescribed blood draining as a treatment for everything from a sore throat to the plague, and some barbers listed it as a service along with haircuts and shaves. The practice finally fell out of vogue after new research showed that it might be doing more harm than good, but leeching and controlled bloodletting are still used today as treatments for certain rare illnesses.

2. Trepanation

Humanity’s oldest form of surgery is also one of its most gruesome. As far back as 7,000 years ago, civilizations around the world engaged in trepanation—the practice of boring holes in the skull as a means of curing illnesses. Researchers can only speculate on how or why this grisly form of brain surgery first developed. A common theory holds that it may have been some form of tribal ritual or even a method for releasing evil spirits believed to possess the sick and mentally ill. Still others argue that it was a more conventional surgery used to treat epilepsy, headaches, abscesses and blood clots. Trepanned skulls found in Peru hint that it was also a common emergency treatment for cleaning out bone fragments left behind by skull fractures, and evidence shows that many of the patients survived the surgery.

3. Mercury

Mercury is notorious for its toxic properties, but it was once used as a common elixir and topical medicine. The ancient Persians and Greeks considered it a useful ointment, and second-century Chinese alchemists prized liquid mercury, or “quicksilver,” and red mercury sulfide for their supposed ability to increase lifespan and vitality. Some healers even promised that by consuming noxious brews containing poisonous mercury, sulfur and arsenic, their patients would gain eternal life and the ability to walk on water. One of the most famous casualties of this diet was the Chinese Emperor Qin Shi Huang, who supposedly died after ingesting mercury pills designed to make him immortal.

From the Renaissance until the early 20th century, Mercury was also used as a popular medicine for sexually transmitted diseases like syphilis. While some accounts claimed the heavy metal treatment was successful in fighting off the infection, patients often died from liver and kidney damage caused by mercury poisoning.

4. Animal Dung Ointments

The ancient Egyptians had a remarkably well-organized medical system, complete with doctors who specialized in healing specific ailments. Nevertheless, the cures they prescribed weren’t always up to snuff. Lizard blood, dead mice, mud and moldy bread were all used as topical ointments and dressings, and women were sometimes dosed with horse saliva as a cure for an impaired libido.

Most disgusting of all, Egyptian physicians used human and animal excrement as a cure-all remedy for diseases and injuries. According to 1500 B.C.’s Ebers Papyrus, donkey, dog, gazelle and fly dung were all celebrated for their healing properties and their ability to ward off bad spirits. While these repugnant remedies may have occasionally led to tetanus and other infections, they probably weren’t entirely ineffective—research shows the microflora found in some types of animal dung contain antibiotic substances.

5. Cannibal Cures

Suffering from persistent headaches, muscle cramps or stomach ulcers? Once upon a time, your local physician may have prescribed an elixir containing human flesh, blood or bone. So-called “corpse medicine” was a disturbingly common practice for hundreds of years. The Romans believed that the blood of fallen gladiators could cure epilepsy, and 12th century apothecaries were known for keeping a stock of “mummy powder”—a macabre extract made from ground up mummies looted from Egypt. Meanwhile, in 17th century England, King Charles II was known for enjoying a draught of “King’s Drops,” a restorative brew made from crumbled human skull and alcohol.

These cannibalistic medicines were thought to have magical properties. By consuming the remains of a deceased person, the patient also ingested part of their spirit, leading to increased vitality and wellbeing. The type of cure prescribed usually corresponded to the type of ailment—skull was used for migraines, and human fat for muscle aches—but getting fresh stock could be a gruesome process. In some cases, the sickly would even attend executions in the hope of getting a cheap cup of the freshly killed person’s blood.

6. Wandering Womb

Ancient Greek doctors believed that a woman’s womb was a separate creature with a mind of its own. According to the writings of Plato and Hippocrates, when a woman was celibate for an extended time, her uterus—described as a “living animal” eager to bear children—could dislodge and glide freely about her body causing suffocation, seizures and hysteria. This curious diagnosis endured in some form into the time of the Romans and Byzantines—well after doctors had learned that the womb was held in place by ligaments.

To prevent their wombs from going on walkabout, ancient women were counseled to marry young and bear as many children as possible. For a womb that had already broken free, doctors prescribed therapeutic baths, infusions and physical massages to try to force it back in position. They might even “fumigate” the patient’s head with sulfur and pitch while simultaneously rubbing pleasant-smelling lotions between her thighs —the logic being that the womb would flee from the bad smells and move back into its rightful place.

7. Babylonian Skull Cure

For the ancient Babylonians, most illnesses were thought to be the result of demonic forces or punishment by the gods for past misdeeds. Doctors often had more in common with priests and exorcists than modern physicians, and their cures usually involved some component of magic. For example, if a patient ground their teeth, the healer might suspect that the ghost of a deceased family member was trying to contact them as they slept. According to ancient necromantic texts, the doctor would recommend sleeping by a human skull for a week as a way of exorcising the spirit. To ensure this disturbing treatment worked, the tooth-grinder was also instructed to kiss and lick the skull seven times each night.