With Halloween approaching, October invites us to indulge in ghost stories. And although we pride ourselves on practising evidence-based medicine, history reminds us that our profession has seen its share of creepy cures and ghastly guidelines. Here are some of the spookiest examples that haunt medicine’s past.

Bloodletting

Dating back to the time of Hippocrates (c. 460–370 BC), bloodletting was promoted as a cure for the imbalance of humors—blood, phlegm, black bile, and yellow bile. Through venesection, arteriotomy, scarification, cupping, and leeches, it was used for seizures, pneumonia, and fevers of all kinds.[1] George Washington’s death in 1799, following the removal of 2.5 L of blood alongside blistering and laxatives, is now thought to have been caused by acute epiglottitis.[2] Today, therapeutic phlebotomy has a narrow role in conditions such as hemochromatosis and polycythemia vera, and medicinal leeches are used in reconstructive surgery, but the practice is no longer the grisly staple it once was.[2,3]

Trepanation

One of the oldest neurosurgical operations, trepanation involved making holes in the skull with the intention of releasing evil spirits. For centuries, the practice was likely driven by religion and mysticism but eventually evolved into a systematic approach to brain trauma in Hippocratic medicine.[4,5] While not a direct ancestor of the modern burr hole, the eerie similarity in principle—gaining access to the intracranial space—remains.

Lobotomy

Intended to reduce the symptoms of mental illness, frontal lobotomy was a type of “psychosurgery” introduced by Portuguese neurologist António Egas Moniz and neurosurgeon Almeida Lima. The procedure severed the white matter connections of the prefrontal cortex, sometimes with an ice pick–like instrument in a transorbital approach.[6] Egas Moniz won the Nobel Prize in 1949 for this “innovation” he called leucotomy, but it is now one of the most criticized medical procedures.[7] Patients were left with profound and enduring changes in function and personality, including apathy, disinhibition, and loss of initiative.[6]

Arsenic and mercury treatments

Arsenic trioxide, traced back to 2000 BC, has the unique distinction of being both medicine and poison. Odorless and tasteless, it became infamous as “inheritance powder,” a favored tool of royal assassins and wives wishing to rid themselves of their husbands.[8] It was prescribed for ulcers, fevers, malaria, psoriasis, and syphilis, and later inspired organoarsenic compounds such as atoxyl, which laid the groundwork for arsenic trioxide’s modern use in leukemia chemotherapy.[8] Arsenic exposure is a double-edged sword, however, as therapeutic margins can be perilously thin, and chronic exposure, whether through groundwater or pharmaceuticals, increases the risk of cancers, neuropathy, and organ damage.[8]

Mercury’s medicinal history is also grim. Once used for a variety of ailments, including syphilis, skin diseases, and diuretics, we now know of the neuropsychiatric consequences of mercury that made felt workers “mad as a hatter” and the toxic global impacts such as through fish exposure.[9]

Is the future of medicine less scary?

Bygone examples of medicine’s horrors abound—asylums and straitjackets, radium cures, and maternal and surgical care without anesthesia or antisepsis. How were we once so confident in practices that now seem so gruesome?

The uncomfortable truth is that we still offer treatments that will, in hindsight, prove unhelpful or even harmful. Not out of malice, but because best practices evolve; sometimes the right questions are elusive, or studies are too costly or impractical. As physicians quip, not everything can be tested in a randomized trial—no one has yet randomized parachutes for skydiving.[10]

This Halloween, as ghosts and ghouls wander our streets, it’s worth remembering that medicine, too, has its hauntings, and the scariest thing may be believing we’ve finally outgrown them.
—Caitlin Dunne, MD

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License [11].

References

1. Greenstone G. The history of bloodletting. BCMJ 2010;52:12-14.

2. National Constitution Center. The mysterious death of George Washington. 14 December 2023. Accessed 2 September 2025. https://constitutioncenter.org/blog/the-mysterious-death-of-george-washington [12].

3. Hackenberger PN, Janis JE. A comprehensive review of medicinal leeches in plastic and reconstructive surgery. Plast Reconstr Surg Glob Open 2019;7:e2555. https://doi.org/10.1097/GOX.0000000000002555 [13].

4. Tsermoulas G, Aidonis A, Flint G. The skull of Chios: Trepanation in Hippocratic medicine. J Neurosurg 2014;121:328-332. https://doi.org/10.3171/2014.4.JNS131886 [14].

5. Martin G. Was Hippocrates a beginner at trepanning and where did he learn? J Clin Neurosci 2000;7:500-502. https://doi.org/10.1054/jocn.1999.0677 [15].

6. Faria MA Jr. Violence, mental illness, and the brain – A brief history of psychosurgery: Part 1 – From trephination to lobotomy. Surg Neurol Int 2013;4:49.

7. Terrier L-M, Lévêque M, Amelot A. Brain lobotomy: A historical and moral dilemma with no alternative? World Neurosurg 2019;132:211-218. https://doi.org/10.1016/j.wneu.2019.08.254 [16].

8. Paul NP, Galván AE, Yoshinaga-Sakurai K, et al. Arsenic in medicine: Past, present and future. Biometals 2022;36:283-301. https://doi.org/10.1007/s10534-022-00371-y [17].

9. Budnik LG, Casteleyn L. Mercury pollution in modern times and its socio-medical consequences. Sci Total Environ 2019:654:720-734. https://doi.org/10.1016/j.scitotenv.2018.10.408 [18].

10. Yeh RW, Valsdottir LR, Yeh MW, et al. Parachute use to prevent death and major trauma when jumping from aircraft: Randomized controlled trial. BMJ 2018;363:k5094. https://doi.org/10.1136/bmj.k5094 [19].