The history of the medical profession is a history of trials and errors - emphasis on the errors. As doctors, researchers, and barbers have searched for cures for various maladies, they've tried some very strange ancient health practices in the name of science, with many of these "cures" leading to a host of health problems of their own.
The reason the Hippocratic Oath exists is, in part, to help protect patients from overzealous doctors who think that their wildly experimental "cure" is the best treatment, regardless of how bad it may be for the patient. But before the words of Hippocrates were widely known, some things ancient people did for their health definitely violated ethical standards, to say the least.
Looking over this list of cruel, misguided, and just plain absurd ancient health customs does make you wonder what procedures we use today that future generations will be totally horrified by... but at least we're not shoving crocodile dung inside of us, right?
Some ancient doctors subscribed to the theory that the body is governed by four "bodily humours:" black bile, yellow bile, phlegm, and blood. When a person fell ill, they believed that this was due to an imbalance of the humours, which could often be corrected by simply getting rid of some of that pesky blood. Leeches were frequently the instrument of choice for this "operation" due to their natural blood-sucking tendencies. However, many surgeons would just cut open a vein and let out a pint or two.
Bloodletting was prescribed by doctors in ancient Greece, Egypt, and Europe (even into the 19th century) for everything from fever, infection, acne, headaches, diabetes, epilepsy, and more. While giving blood can have some health benefits (especially in men at risk of heart attack), most doctors agree that your blood is more effective inside your body rather than out - though modern doctors have successfully used leeches to aid in difficult reattachment surgeries.
A number of ancient cultures have used animal dung of all sorts to treat a wide variety of illnesses. The ancient Egyptians would rub it on wounds - and in their eyes - and even use it as a contraceptive. Crocodile dung was formed into a kind of proto-diaphragm that, not surprisingly, was not only ineffective at preventing pregnancy (actually, it may have increased the odds of conception) it also came with its own set of health complications.
"Trepanning" is the medical name for "drilling a hole in your head." While archeologists, anthropologists, and medical professionals are confused as to why people thought this was a good idea, there is a long history of boring into peoples skulls as a treatment for mental disorders, and paradoxically, to relieve headaches. Skulls have been found with holes in them across Europe, Africa, and the Americas - some even showing bone growth, which points to patients actually surviving this brutal treatment.
If humans have tried using feces for health purposes, one would probably imagine they've tried using urine as well - and one would imagine correctly. Urine has been used by a number of cultures as both a tool for diagnosis and as a treatment for wide spectrum of ailments. Pee has been used as a cleaning agent, as face wash, and no less an authority as Madonna has claimed to use it to cure athlete's foot. Ancient Romans found that the ammonia in urine helps to lift away stains. So, in a perfectly logical move, they used it as a teeth whitener.