Bezoar Stones, the Universal Antidote: More Than a Mistake?

It is fair to say that the history of medicine has been something of a hit and miss affair. Without modern technology to aid in our understanding of the root causes of ailments, there was a lot of guesswork and outright quackery in the mix for much of the time.

This is not to say that it was anyone’s fault in particular. Our understanding of anatomy and biology was limited by technology: we did not conceive of germs, viruses or bacterial infections, for example, because we lacked the ability to find them. We might as well have believed in foul smelling swamp gases carrying disease, as indeed we did.

In fact, we had only one proper process for the development of medicine, and that was trial and error. Much of our history of medicine is based on finding out what worked and using that, and as you might expect this was an imperfect science at best.

It is true that we sometimes hit the nail on the head, often elevating our greatest discoveries almost to the status of religious doctrine. Our understanding of general hygiene, for instance, found itself intermingled with dogma, with illness resulting from careless hygiene being seen as god’s punishment.

As an example. consider the wisdom of a Jewish or Islamic diet in a desert environment without refrigeration where pork and shellfish would be quick to spoil and germs could be easily passed from utensil to utensil. Seen through this lens the dietary restrictions were entirely prudent for the time, and although perhaps less essential in the modern world they survive as relics of ancient necessity.

However, amidst these successes there were plenty of misidentifications, which largely came about through misunderstanding or even outright fakery. Sometimes however a mistake endures despite such errors, and sometimes it takes a signal moment or act to finally dispel these myths.

So it was with bezoar stones, perhaps the grossest of all antidotes.

Delicious!

Bezoar stones are not the most appealing dietary supplement. These hard masses form in the intestines of humans and animals. In their simplest form they are accreted collections of undigested foods, but they can be formed by multiple processes, some harmless, some highly harmful.

The word “bezoar” gives a hint as to how they were originally perceived. It comes from the Persian word pād-zahr (پادزهر), which literally translates to “antidote” and indeed such stones were seen as medicinal from at least the 11th century in the Middle East.

The famous physician Ibn Zuhr considered them to have highly valuable medical properties, and the book of magic known as the Ghāyat al-Ḥakīm also mentions them on several occasions. Both sources passed their knowledge to Europe in the 12th century, and it was through these that the west came to hear of these uses of bezoar stones.

Bezoars recovered from various animals were used as prophylactics, placed into the bottom of drinking vessels. It was thought that any poison introduced into the drink would be neutralized by the bezoar, rendering the drink safe.

The stones naturally became highly prized, and it was several centuries before the idea of them as a universal antidote faced any significant challenge. It only be in the late 16th century that the idea was finally quashed and it took a Frenchman and a practical demonstration to do so.

The French surgeon Ambroise Paré, a forward thinking man aided by a more modern medical understanding than the 11th century Persians, had become convinced through his research that bezoar stones could not function as had been described. However to convince a skeptical public he needed something more concrete.

Happily, he had a volunteer on which to experiment. A cook in the court of the French King Charles IX had been found guilty of a crime and sentenced to death. At Paré’s request he was permitted to avoid his sentence of hanging provided instead he submitted to drinking poison from a cup containing a bezoar stone.

The cook may have expected to survive the poison cup but, if that were true, he was out of luck. After drinking from the cup with the bezoar stone he endured seven hours of gastrointestinal agony before finally perishing. The bezoar had done nothing to save him.

In truth by this time there had been much doubt about the efficacy of bezoar stones. Certainly nobody in 16th century France would think to entirely rely on their supposed medicinal properties, but it took this final demonstration to, largely, consign them to history.

But the question remains: why? Why had anyone assumed that a gastrointestinal blockage would have the power to render poisons harmless? Why had such a concept endured for so long, and so far into the modern age? 

Sometimes an old wives’ tale is just that, easily disproved. But sometimes at the heart of a myth there is a kernel of truth, a demonstrable core which survives even the microscopic examination of modern science. And so it is, or at least might be, with bezoar stones.

In 2013, Gustaf Arrhenius and Andrew A. Benson of the Scripps Institution of Oceanography revisited the idea of bezoar stones as an antidote to poison, and the conclusions they drew were surprising to say the least. 

Could bezoar stones neutralize poison? Amazingly, while ineffective against most poisons, they seemed to work when introduced to a liquid containing that most invisible and deadly poison of all: arsenic.

Bezoar stones which had been immersed in a solution containing arsenic were found to react chemically with the lethal element in the liquid. The two actively toxic compounds in the drink: arsenite and arsenate, were both rendered harmless by the bezoar.

Bezoars commonly contain undigested hair which work as nucleation sites for the stones, and the proteins which make up the hair contain compounds of sulfur. Arsenite in the solution will bind itself to these compounds, removing the toxic compound from the liquid.

Bezoar stones also often contain something called “brushite”, a crystalline compound containing phosphor. The arsenate in the solution would similarly react with this compound, and with both dangerous arsenic-based chemicals removed from the solution, the drink is rendered harmless.

And so it seems that, far from being an old wives’ tale, bezoar stones may indeed work to neutralize poison, so long as that poison is arsenic. Not everything from history is quackery, and sometimes truth in medicine can come from the least expected places.

Not that we suggest trying it.

Top Image: Bezoar stones in the Munich Residenz (Schtone / CC BY-SA 3.0)