Medieval Medicine and Deadly Cures

Before modern medicine transformed healthcare, medieval doctors were often more dangerous than the diseases they claimed to treat. Armed with bizarre theories, deadly substances, and procedures that would horrify modern patients, these well-meaning healers accidentally killed more people than they saved. From bloodletting that drained patients to death, to mercury treatments that poisoned entire families, to skull drilling that scrambled brains, medieval medicine reads like a horror story written by history itself. These weren’t evil doctors—they were simply working with deadly ignorance in an age when good intentions paved the road to medical hell.

Understanding Medieval Medical Mindset

The Four Humors Theory

Medieval doctors based their treatments on the ancient Greek theory of four bodily humors:

Blood (Hot and Wet): Associated with spring, air, and sanguine personality Yellow Bile (Hot and Dry): Linked to summer, fire, and choleric temperament
Black Bile (Cold and Dry): Connected to autumn, earth, and melancholic mood Phlegm (Cold and Wet): Related to winter, water, and phlegmatic nature

Doctors believed illness resulted from imbalanced humors, leading them to use treatments designed to restore balance—often with deadly consequences.

Medieval Medical Authority Sources

Ancient Greek Texts: Hippocrates and Galen’s writings treated as absolute truth Religious Doctrine: Church teachings that disease was divine punishment or test Astrological Beliefs: Planetary positions supposedly affected health and treatment timing Folk Traditions: Oral remedies passed down through generations without scientific testing

This combination of outdated theory, religious dogma, and superstition created a perfect storm of medical malpractice.

Why Medieval Doctors Were So Dangerous

No Understanding of Germs: Bacteria and viruses wouldn’t be discovered for centuries No Anesthesia: All procedures performed on conscious, screaming patients No Antiseptics: Wounds routinely became infected, leading to death No Scientific Method: Treatments weren’t tested—if patients died, it was “God’s will” Social Authority: Doctors couldn’t be questioned, even when killing patients regularly

The 15 Most Deadly Medieval Medical Treatments

Ranked by death toll and horror factor

Tier 1: Mass Killers (Highest Death Rates)

1. Bloodletting – The Great Drainer

• Method: Cutting veins, using leeches, or cupping to remove “excess” blood
• Death Rate: 60-80% for severe applications
• Why It Killed: Patients died from blood loss, shock, and infection
• Deadly Details:
  • Doctors removed up to 4 pints of blood (modern donations are 1 pint)
  • Used dirty instruments that spread infection
  • Repeated treatments weakened patients until death
  • Believed more blood = more illness, so sicker patients lost more blood
• Famous Victims: Possibly George Washington, countless medieval patients
• Modern Parallel: Extreme blood donations or untreated internal bleeding

2. Mercury Treatments – The Slow Poisoner

• Method: Ingesting, injecting, or rubbing mercury on skin for various ailments
• Death Rate: 50-70% with heavy treatments
• Why It Killed: Mercury poisoning attacks nervous system, kidneys, and brain
• Deadly Details:
  • Used for syphilis, skin conditions, and “melancholy”
  • Mercury vapor poisoned entire households
  • Symptoms included tooth loss, brain damage, kidney failure
  • Doctors increased doses when patients got sicker from mercury
• Famous Victims: Many European nobility, hat makers (Mad Hatter syndrome)
• Modern Parallel: Heavy metal poisoning from industrial accidents

3. Trepanation – The Skull Drill

• Method: Drilling or scraping holes in skull to release “evil spirits” or pressure
• Death Rate: 70-90% in medieval times
• Why It Killed: Brain infection, bleeding, shock, and brain damage
• Deadly Details:
  • Used primitive tools like sharp stones or metal spikes
  • No understanding of brain anatomy or sterile technique
  • Holes often became infected with fatal brain abscesses
  • Sometimes removed large skull sections
• Famous Victims: Unknown, but archaeological evidence shows widespread practice
• Modern Parallel: Lobotomies (which continued into the 1960s)

4. Purging and Vomiting – The Gut Wrecker

• Method: Forcing violent vomiting and diarrhea to expel “evil humors”
• Death Rate: 40-60% with extreme purging
• Why It Killed: Dehydration, electrolyte imbalance, and internal damage
• Deadly Details:
  • Used toxic substances like antimony and hellebore
  • Patients vomited and defecated until unconscious
  • Continued treatments even as patients weakened
  • Children and elderly died fastest from dehydration
• Famous Victims: Many royal children, including possible heirs to thrones
• Modern Parallel: Severe eating disorders or food poisoning

5. Cauterization – The Human Branding

• Method: Burning flesh with hot irons to “seal wounds” and treat illness
• Death Rate: 50-70% for major applications
• Why It Killed: Shock, infection, and severe burns
• Deadly Details:
  • Used red-hot metal rods on open wounds
  • Burned large skin areas to treat internal problems
  • No pain relief—patients often died from shock
  • Burns frequently became infected and gangrenous
• Famous Victims: Medieval soldiers, nobility seeking “cures”
• Modern Parallel: Severe burn victims without proper treatment

Tier 2: Dangerous Regulars (High Death Rates)

6. Urine Therapy – The Golden Poison

• Method: Drinking urine, urine enemas, and bathing in urine
• Death Rate: 20-40% when used extensively
• Why It Killed: Infections, poisoning, and worsening of underlying conditions
• Deadly Details:
  • Fresh and aged urine used for different ailments
  • Urine enemas caused internal infections
  • Bathing in urine led to skin infections
  • Sometimes used other people’s urine, spreading diseases
• Famous Victims: Various medieval patients seeking “natural” cures
• Modern Parallel: Drinking contaminated water or untreated sewage exposure

7. Animal Organ Transplants – The Cross-Species Killer

• Method: Transplanting animal organs or blood into humans
• Death Rate: 90-95% (almost always fatal)
• Why It Killed: Rejection reactions, infections, and incompatible biology
• Deadly Details:
  • Pig hearts sewn into human chests
  • Goat blood transfused into patients
  • Raw animal organs eaten to “absorb” animal strength
  • No understanding of immune system rejection
• Famous Victims: Experimental patients of ambitious doctors
• Modern Parallel: Organ rejection without anti-rejection drugs

8. Metallic Poisons as Medicine – The Elemental Killers

• Method: Using lead, arsenic, antimony, and other toxic metals as treatments
• Death Rate: 40-80% depending on dosage and duration
• Why It Killed: Heavy metal poisoning affecting all organ systems
• Deadly Details:
  • Lead used for stomach problems (caused brain damage)
  • Arsenic for skin conditions (caused organ failure)
  • Antimony for purging (caused violent illness)
  • Metals accumulated in body, causing slow death
• Famous Victims: Roman and medieval nobility, painters using lead
• Modern Parallel: Industrial heavy metal poisoning

9. Extreme Heat and Cold Therapy – The Temperature Torture

• Method: Exposing patients to extreme temperatures to “balance humors”
• Death Rate: 30-50% for extreme applications
• Why It Killed: Hypothermia, hyperthermia, shock, and organ failure
• Deadly Details:
  • Patients buried in snow for “cooling”
  • Locked in overheated rooms to “sweat out illness”
  • Alternating extreme hot and cold treatments
  • Elderly and children died fastest from temperature shock
• Famous Victims: Patients seeking cures for fevers and “hot” diseases
• Modern Parallel: Exposure deaths from hypothermia or heat stroke

10. Poisonous Plant Remedies – The Garden of Death

• Method: Using toxic plants like foxglove, nightshade, and hemlock as medicine
• Death Rate: 30-60% depending on plant and dosage
• Why It Killed: Plant toxins attacking nervous system, heart, and other organs
• Deadly Details:
  • Foxglove for heart problems (caused heart attacks)
  • Belladonna for pain relief (caused hallucinations and death)
  • Hemlock for “calming” (caused paralysis and suffocation)
  • Dosages based on guesswork, not science
• Famous Victims: Socrates (hemlock), countless medieval patients
• Modern Parallel: Accidental poisoning from misidentified plants

Tier 3: Frequently Fatal (Moderate to High Death Rates)

11. Primitive Surgery – The Butcher’s Table

• Method: Cutting into bodies without anesthesia, antiseptics, or proper tools
• Death Rate: 50-80% for major procedures
• Why It Killed: Infection, blood loss, shock, and surgical trauma
• Deadly Details:
  • Used same tools for surgery, farming, and butchering
  • No hand washing or sterilization
  • Patients often died from shock during procedure
  • Post-surgical infections were almost guaranteed
• Famous Victims: Medieval patients requiring amputations or tumor removal
• Modern Parallel: Surgery in unsanitary conditions without proper training

12. Skull Binding and Deformation – The Head Crusher

• Method: Binding infant skulls to create desired head shapes
• Death Rate: 20-40% of bound children
• Why It Killed: Brain compression, developmental problems, and skull fractures
• Deadly Details:
  • Tight bindings restricted brain growth
  • Caused seizures, mental disabilities, and early death
  • Sometimes combined with other procedures
  • Continued despite obvious harm to children
• Famous Victims: Children of various cultures practicing skull modification
• Modern Parallel: Severe head trauma or brain compression injuries

13. Exorcism and Spiritual Medicine – The Faith Killer

• Method: Violent physical and psychological abuse to drive out “demons”
• Death Rate: 15-30% for extreme exorcisms
• Why It Killed: Physical abuse, starvation, dehydration, and psychological trauma
• Deadly Details:
  • Beating patients to drive out evil spirits
  • Starvation to “weaken demons”
  • Forced consumption of holy water or blessed substances
  • Restraints that caused circulation loss and death
• Famous Victims: Mentally ill patients throughout medieval Europe
• Modern Parallel: Abuse in unregulated mental health facilities

14. Primitive Dentistry – The Mouth Mangler

• Method: Tooth extraction and oral surgery with crude tools
• Death Rate: 10-25% for major dental work
• Why It Killed: Infection, blood loss, and complications from crude procedures
• Deadly Details:
  • Used pliers, hammers, and chisels on teeth
  • No anesthesia for tooth extraction
  • Infections spread to brain through facial bones
  • Sometimes broke jaw bones during extractions
• Famous Victims: Medieval patients with dental problems
• Modern Parallel: Dental procedures without proper sterilization

15. Starvation Therapy – The Hunger Cure

• Method: Deliberately starving patients to “purify” their bodies
• Death Rate: 20-40% for extended starvation
• Why It Killed: Malnutrition, organ failure, and weakened immune system
• Deadly Details:
  • Believed food “fed” diseases
  • Starved patients for weeks during illness
  • Combined with other treatments that weakened patients
  • Children and elderly died fastest from malnutrition
• Famous Victims: Medieval patients with various illnesses
• Modern Parallel: Severe anorexia or famine conditions

Survival Rate Comparisons: Medieval vs. Modern Medicine

Common Medical Conditions: Then vs. Now

Condition	Medieval Survival Rate	Modern Survival Rate	Treatment Difference
Broken Bone	30-50%	95-99%	Splinting vs. proper setting and surgery
Severe Infection	10-20%	90-95%	Bloodletting vs. antibiotics
Heart Attack	5-10%	80-90%	Prayer vs. emergency surgery
Childbirth Complications	20-40%	99%+	Crude tools vs. sterile surgery
Appendicitis	10-15%	98-99%	Herbal remedies vs. surgical removal
Severe Burns	10-30%	70-90%	Cauterization vs. skin grafts
Pneumonia	20-30%	95%+	Bloodletting vs. antibiotics
Diabetes	0% (always fatal)	90%+ (with treatment)	No treatment vs. insulin

Surgical Procedure Survival Rates

Medieval Surgery (500-1500 CE):

• Amputation: 20-40% survival
• Tumor removal: 10-30% survival
• Cataract surgery: 30-50% survival
• Kidney stones: 25-45% survival

Modern Surgery (2020s):

• Amputation: 95-98% survival
• Tumor removal: 85-95% survival
• Cataract surgery: 99%+ survival
• Kidney stones: 98-99% survival

Why Medieval Medicine Was So Deadly

Lack of Germ Theory: Didn’t know about bacteria, viruses, or infection No Anesthesia: Patients died from shock and pain during procedures No Antiseptics: Every cut became infected Wrong Theories: Humoral theory led to treatments that made patients worse No Quality Control: Anyone could claim to be a doctor Religious Interference: Medical advancement often forbidden as heretical

Modern Medical Horror Parallels

Historical Medical Malpractice That Continued Into Modern Times

Lobotomies (1930s-1960s):

• Similar to medieval trepanation
• Destroyed brain tissue to “cure” mental illness
• 40,000+ performed in US alone
• Many patients left vegetative or dead

Thalidomide Crisis (1950s-1960s):

• “Safe” sleeping pill for pregnant women
• Caused severe birth defects in 10,000+ babies
• Similar to medieval faith in untested remedies

Radium Medicine (1900s-1930s):

• Radioactive elements used as cure-all
• Similar to medieval mercury treatments
• Caused cancer, death, and radiation poisoning

Bloodletting Revival (1800s-early 1900s):

• Medieval practice continued for centuries
• George Washington possibly killed by bloodletting in 1799
• Didn’t fully disappear until 20th century

Why Bad Medicine Persists

Authority Worship: Patients trust doctors without question Confirmation Bias: Ignoring evidence that treatments don’t work Economic Incentives: Profitable treatments continued despite harm Slow Scientific Progress: Takes decades to prove treatments harmful Cultural Resistance: People resist changing traditional practices

Books for Readers Fascinated by Medical History

Academic and Historical Sources

1. “The Greatest Benefit to Mankind” by Roy Porter

• Comprehensive history of medicine from ancient times to modern
• Covers medieval practices in historical context
• Academic but accessible writing style

2. “Quackery: A Brief History of the Worst Ways to Cure Everything” by Lydia Kang and Nate Pedersen

• Entertaining look at historical medical mistakes
• Covers medieval through modern quackery
• Well-illustrated with historical examples

3. “Bad Medicine: Misconceptions and Misuses Revealed” by Christopher Wanjek

• Modern and historical medical mistakes
• Scientific approach to understanding why bad medicine persists
• Covers psychological aspects of medical belief

Popular History and Narrative

4. “The Butchering Art” by Lindsey Fitzharris

• Victorian surgery and the introduction of antiseptics
• Shows progression from medieval-style surgery to modern practice
• Engaging narrative style with historical detail

5. “Sawbones: A Hilarious Tour of Medical History” by Justin McElroy and Sydnee McElroy

• Humorous but educational approach to medical history
• Podcast-based book covering various historical treatments
• Accessible for general audiences

6. “Blood and Guts: A Working Guide to Your Own Insides” by Richard Walker

• Medical history combined with anatomy education
• Good for understanding why medieval treatments failed
• Visual approach to medical education

Specialized Topics

7. “Mercury Rising: John Glenn, John McCain, and the Fight to Ban the Deadliest Poison” by Robert F. Kennedy Jr.

• Modern mercury poisoning and historical context
• Connects medieval mercury treatments to modern environmental issues
• Political and scientific analysis

8. “The Lobotomist” by Jack El-Hai

• Biography of Walter Freeman and the lobotomy craze
• Shows how medieval-style thinking persisted into modern times
• Psychological and medical analysis

Frequently Asked Questions

Q: Were medieval doctors actually trying to kill their patients? A: No, medieval doctors genuinely believed they were helping. They worked within the medical knowledge of their time, which was unfortunately based on incorrect theories and lacked scientific testing.

Q: Why didn’t people stop using treatments that obviously didn’t work? A: Several factors: authority of medical tradition, lack of scientific method to test treatments, religious beliefs that suffering was divine will, and confirmation bias (remembering successes, forgetting failures).

Q: How did anyone survive medieval medicine? A: Many people avoided doctors entirely, relying on folk remedies that were often less harmful. The human body is also remarkably resilient, and some patients recovered despite, not because of, medical treatment.

Q: Were there any effective medieval medical treatments? A: Yes, some herbal remedies had genuine medicinal properties (willow bark for pain relief, foxglove for heart conditions), bone setting techniques, and basic wound care. However, effective treatments were often mixed with harmful ones.

Q: When did medicine start becoming genuinely helpful rather than harmful? A: The major turning point was the discovery of germ theory in the 1860s-1880s, followed by the development of anesthesia, antiseptics, and antibiotics. By the early 1900s, medical treatment became more helpful than harmful.

Q: How do we know about medieval medical practices if records were limited? A: Sources include medical texts and manuscripts, archaeological evidence (especially from cemetery excavations), court records, religious writings, and some personal accounts from literate patients.

Q: Are there any medieval medical practices still used today? A: Very few. Some herbal remedies have evolved into modern medications, and certain surgical techniques have ancient origins, but modern versions are vastly improved with scientific understanding and safety measures.

Q: Why did educated people believe in obviously harmful treatments like bloodletting? A: The practice was supported by respected authorities (Galen, Hippocrates), appeared to have scientific logic based on humoral theory, and confirmation bias made failures seem like exceptions rather than proof the treatment was wrong.

The Psychology of Medical Belief

Why Harmful Treatments Persisted

Authority Bias: Ancient Greek and Roman physicians were considered infallible authorities Survivorship Bias: Only successful cases were remembered and recorded Placebo Effect: Patients sometimes felt better due to attention and care, not treatment Post Hoc Reasoning: Recovery after treatment was assumed to be caused by treatment Social Pressure: Questioning medical authority was considered heretical or disrespectful

How Patients Rationalized Deadly Treatments

Divine Will: Deaths were attributed to God’s plan, not medical failure Moral Failing: Patient deaths blamed on sin or insufficient faith Natural Course: “The disease was too advanced” when treatment failed Individual Variation: “This treatment doesn’t work for everyone” Heroic Suffering: Enduring painful treatment seen as virtuous

Lessons for Modern Medicine

Parallels in Contemporary Healthcare

Unproven Treatments: Alternative medicine with no scientific evidence Authority Worship: Patients afraid to question doctors or seek second opinions Profit Motives: Expensive treatments promoted despite limited effectiveness Cultural Resistance: Difficulty changing established medical practices Confirmation Bias: Focusing on success stories while ignoring failures

How Modern Medicine Avoids Medieval Mistakes

Scientific Method: Controlled studies and peer review Evidence-Based Practice: Treatments proven effective before adoption Regulatory Oversight: Government agencies monitor drug and device safety Informed Consent: Patients understand risks and benefits Continuous Monitoring: Ongoing surveillance for treatment effectiveness and safety

The Horror and Hope of Medical History

Medieval medicine serves as both a horror story and a testament to human progress. The same impulse that drove medieval doctors to drill holes in skulls—the desire to heal suffering—eventually led to modern medical miracles. The difference lies in the development of scientific methods, understanding of anatomy and physiology, and rigorous testing of treatments.

Understanding this medical horror story helps us appreciate how far we’ve come while remaining vigilant against the return of harmful practices. The psychology that made bloodletting seem logical for centuries—authority worship, confirmation bias, and resistance to change—still exists today and can lead to modern medical mistakes.

The transition from medieval medicine to modern healthcare represents one of humanity’s greatest achievements. In just a few centuries, we moved from treatments that killed most patients to interventions that save millions of lives annually. This transformation required not just scientific discoveries, but fundamental changes in how we think about evidence, authority, and the nature of disease.

Medieval doctors weren’t evil—they were working with the best knowledge available to them, trapped by theories that seemed logical but were fundamentally wrong. Their deadly cures remind us that good intentions without scientific evidence can be more dangerous than no treatment at all. As we continue advancing medical knowledge, the horrors of medieval medicine serve as a powerful reminder of why evidence-based practice, humility in the face of uncertainty, and constant questioning of medical authority remain essential for keeping doctors as healers rather than accidental killers.

The blood-soaked history of medieval medicine ultimately tells a story of hope: if humanity can progress from trepanation to brain surgery, from bloodletting to organ transplants, and from mercury poisoning to precision drug therapy, there’s no limit to how much further medical science can advance in healing rather than harming those who seek care.