Hektoen International

A Journal of Medical Humanities

The bizarre history of the bezoar

Howard Fischer
Uppsala, Sweden

“As for the bezoar [we removed] …we have restricted ourselves from employing its therapeutic power in the practice of medicine.”1
– John Moffat, M.D.

Fully extracted gastric trichobezoar composed of hair extensions cast in the shape of the stomach and small bowel. The arrow indicates the portion of the trichobezoar that approximated the pylorus of the stomach. Text and photo from Devin Flaherty et al, “Rapunzel syndrome due to ingested hair extensions: Surgical and psychiatric considerations,” International Journal of Surgery Case Reports 17 (2015):155-7 via ResearchGate. CC BY-NC-ND 4.0

A bezoar is a compact mass of material that may be found in the digestive tract of mammals, including humans. Bezoars in humans may cause problems. Those found in other animals were once thought to have medical or magical properties. The belief in bezoars’ protective and curative properties arose in the Middle East and came to Europe in the eleventh century. The word “bezoar” might be from the Persian panzehr, meaning a “counter-poison,” an antidote, or from the Arabic badzehr, meaning the same thing. In Arabic there is no “p” sound, so “b” (or “f”) takes its place.2 There is also a Turkish goat (Capra aegagrus) known as the bezoar.3

These masses have long been found in the gastrointestinal (GI) tract of sheep, deer, antelope, goats, and oxen. After the “discovery” of the New World, bezoars were also found in llamas4 and beavers.5 Europeans considered the bezoar a universal antidote, capable of neutralizing any known poison. These masses were also worn as amulets to protect the wearer from madness, rabies,6 cholera, and leprosy.7 Bezoars were rare and valuable, being found in only one of 100 animals killed. Queen Elizabeth I (1558–1603) wore a bezoar set in a golden ring,8 and other wealthy people had golden containers made to store—and show off—this treasured object. Bezoars were worth more than their weight in gold.9

Ambroise Paré (1510–1590), surgeon to King Charles IX of France, was skeptical about the poison-neutralizing power of bezoars. With the permission of the king and of a man condemned to hang for stealing a silver tray, he gave the prisoner poison, followed by bezoar material. Had the bezoar saved the man, he would have been pardoned. However, he died in agony from the poison. King Charles joined the skeptics.10

Western medicine more or less forgot about bezoars, until they were described in humans. The first reported case of a patient in the West with a bezoar was in 1779 by a Dr. Baudamont. After his case report, nearly 150 years elapsed until a 1914 report of seventy-six cases of bezoars in humans.11 Bezoars in humans are usually classified according to the composition of the mass. Phytobezoars (the most common type) are made of undigested plant material. A sub-category of phytobezoars are diospyrobezoars, made of unripe persimmons, and mostly seen in Japan and the Southwestern US. Trichobezoars contain hair and accompany trichotillomania with hair-eating. Lactobezoars are made of milk proteins, and pharmacobezoars of medications.

The list of plant sources of phytobezoars is extensive and includes celery, pumpkin, parsnips, Brussels sprouts, mushrooms, popcorn, mangos, figs, and grape skins.12 Pharmacobezoars may result from the use of enteric-coated medications, which use an insoluble carrier substance to protect the active ingredient from stomach acid, or from slow-release drugs coated with cellulose acetate. The antacid Gaviscon (sodium alginate and bicarbonate), when given to newborns with gastroesophageal reflux, has produced bezoars.13 An overdose of the antidepressant venlafaxine has produced a gastric bezoar.14

Other substances found in human bezoars include nails, screws, pebbles, coins, chewing gum, paraffin, shellac, cloth, cotton threads (in a tailor), gauze, matches, honeycombs, wood dust (in a carpenter), plastic, paper, and synthetic fibers from a carpet.16,17 A bezoar has been reported composed of matzah, the unleavened bread eaten during the eight days of the Jewish Passover.18

Although bezoars can occur in people with normal GI tract anatomy and physiology, and without pica (the eating of non-food substances), there are risk factors that make bezoar formation somewhat more likely. These include partial gastrectomy, decreased stomach acid production, gastroparesis, post-surgery adhesions, diabetes, cystic fibrosis, mechanical ventilation, problems with chewing, and excessive fiber intake.19,20

Complications that may result from the presence of bezoars are GI tract obstruction, ulceration of the GI mucosa, and eventually perforation with resultant peritonitis, a potentially fatal condition. Only 0.4–4 % of all cases of GI obstruction are due to bezoars. These are mainly in the stomach and small intestine.21

Today, bezoars are used in traditional Chinese medicine. “Calculus bovis,” ox bezoars (or gallstones), are still bought and sold, including via the internet. They are said to have antipyretic and anti-inflammatory actions.22 Bezoars from the Malayan porcupine (Histrix brachyra) are used in Malaysia as a poison antidote and to cure epilepsy, typhoid fever, hepatitis, diabetes, and cancer. The belief in the effectiveness of this phytobezoar originated in the idea that the porcupine heals quickly when sick, and that its diet consists of plants considered medicinal. Five hundred milligrams of the bezoar sell for between USD $66–220. The authors of one article23 suggest the need for detailed chemical analysis of this substance, and possibly clinical trials of its efficacity.

Current diagnosis of human bezoars is by ultrasound examination and computerized tomography scan. Endoscopy is the “diagnostic method of choice for gastric bezoars.”24 Some phytobezoars have been dissolved with the use of enzymatic solutions, dispensing with the need for surgical removal.

Finally, when thinking about the notions of ancient physicians, we have learned that some bezoars contain calcium and magnesium phosphates, and that these substances can act as chelating (binding) agents25 and absorb arsenic that is in solution—thus serving, in effect, as an antidote.


  1. John Moffat et al. “Gastric bezoar.” Can Med Ass J, 87, October 13, 1962.
  2. Katherine Eng et al. “Gastrointestinal bezoars: History and current treatment paradigms.” Gastroenterol Hepatol (NY), 8(11), 2012.
  3. Maurizio Gentile. “Gastrointestinal bezoars. Review of the literature and report of a rare case of pumpkin seed rectal impaction.” Asian Journal of Surgery online, May 22, 2023.
  4. Loraine Fick. “The magical medicine of bezoars.” HowStuffWorks. https://science.howstuffworks.com/life/biology-fields/magical-medicine-of-bezoars.htm.
  5. Maria Barroso. “Bezoar stones, magic, science and art.” Geological Society, London, Special Publications, November 2013.
  6. Urban Maes. “Bezoars, with the report of an additional case of phytobezoar.” Ann Surg, 88(4), 1928.
  7. Fick, “Magical medicine.”
  8. Amelia Soth. “From the belly of a goat to the mouth of a king,” J-STOR Daily, September 20, 2018.
  9. Barroso, “Bezoar stones.”
  10. Eng et al, “Gastrointestinal bezoars.”
  11. Maes, “Additional case.”
  12. “Bezoar.” Health Jade. https://healthjade.com/bezoar/.
  13. Konstantinos Paschos et al. “Pathophysiological and clinical aspects of the diagnosis and treatment of bezoars.” Ann Gastroenterol, 32(3), 2019.
  14. Dennis Djogovic et al. “Gastric bezoar following venlafaxine overdose.” Clinical Toxicology, 45(6), 2007.
  15. Elias Chahine et al. “Recurrent gastric metal bezoar: A rare cause of gastric outlet obstruction.” BMJ Case Reports, September 27, 2017.
  16. Paschos et al, “Pathophysiological.”
  17. “Bezoar.” Wikipedia.
  18. Amit Sastry et al. “The perils of Passover: Small bowel obstruction from a matzah bezoar.” IMAJ, 16, April 2014.
  19. Eng et al, “Gastrointestinal bezoars.”
  20. Thiruvelan. “Bezoar.” Gastrodigestivesystem.com, April 9, 2013. https://gastrodigestivesystem.com/stomach/bezoar
  21. Gin Law et al. “Colonic phytobezoar as a cause of large bowel obstruction.” BMJ Case Reports, April 9, 2015.
  22. Omar Fabián. “The lure of the bezoar endures.” MRS Bulletin, 44(968), 2019.
  23. Chu Shan Tan. “A traditional folk medicine in Malaysia: Porcupine bezoar.” Oriental Pharmacy and Experimental Medicine, March 2019.
  24. Eng et al, “Gastrointestinal bezoars.”
  25. Barroso, “Bezoar stones.”

HOWARD FISCHER, M.D., was a professor of pediatrics. He is now thankful that his mother told him not to swallow his bubblegum.

Fall 2023



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