During the 16th century, Europeans were leeched an average of 78.4 times over the course of their lives. Bloodletting was a key component of medicine at that time, as physicians perpetuated the thousand-year belief that modulating a patient's blood could treat the entire spectrum of human disease. People generally required leeching two or three times per year, from infancy through old age. Leeches were often applied to newborns within minutes of birth, in some cases while they were still exiting the womb.
The concept behind bloodletting was that there are "humors" in the blood, essences of malady and health that can be lowered or raised by changing the volume of blood within the body. If someone had a cold, for example, leeches would draw down the level of afflicted blood, hastening recovery. If the cold persisted, the doctor simply applied more leeches. If it developed into pneumonia, the leeches had been drawing down the wrong humors and the physician was flogged for malpractice.
The range of ailments for which bloodletting was prescribed ran from the likes of smallpox and tuberculosis to food poisoning, depression, epilepsy, migraines, strep throat, tendonitis, hemophilia, and snoring — making it one of the most popular remedies available. Its popularity also hinged on the misplaced belief that being covered with leeches is somehow not completely revolting.
While the idea of using sanguivorous worms may make today's doctors flinch (and today's patients panic), by the standards of the 16th century it was comparatively tame. Facial scrapings, bone peels, and partial drowning were employed in cases where bloodletting proved insufficient.
A persistent cough was sometimes cured with the use of a "lung hook," a curved, barbed iron tube that was threaded between the ribs. The procedure was always performed on the right lung, as the left was deemed the provenance of the Devil's breath. A common treatment for a broken leg was to break the other leg in the same place, so that the two could heal together. Otherwise, the theory went, the broken leg would mend unevenly, causing a pronounced limp or "breakfoot gait."
In fact, leeches weren't the only animals used in medicine. Eczema was thought to be improved by resting the affected patch of skin on an irate pig overnight. Victims of cholera were tied to a wolf and placed into a burlap sack, while family members knelt nearby singing hymns. There are even recorded instances, though rare, of sewing mice to patients' arms as a way to combat sleepwalking.
One begins to understand why people were said to be doing very well if they lived past the age of 30.