In my novel ‘Galileo’s Revenge’, our hero Galileo Galilei has to solve the suspicious death of Grand Duke Francesco de’ Medici (1541-87). In the course of his investigation, Galileo turns to the work of French barber-surgeon Ambroise Paré (c.1510-90), especially the treatise on poisons. In that work, along with many other topics and toxins, Paré devotes a chapter to ‘Bezoar and Bezoarticke medicines’.

What was Bezoar?

From classical times in Europe, up until Paré’s day and beyond, there were a number of universal panaceas and antidotes on the apothecary’s shelves. There was ‘Mithridatium’, for example, supposedly the personal formulation of King Mithridates VI of Pontus (pre-120-63BC). That contained some 50 ingredients. An alternative was ‘Theriac’, containing even more ingredients, and compounded according to closely guarded recipes. In the Middle Ages, this was imported into England as ‘Venice treacle’. (The featured image above shows the preparation of Theriac in an illustration by an unknown master1 from the medieval health manual Tacuinum sanitatis.)

But Bezoar was rather different.

On the name and nature of Bezoar

Allow Paré to explain:

‘An Antidote or Counter-poyson is by the Arabians in their mother tongue termed “Bedezahar”, as “the preservers of life”. This word is unknowne to the Greekes and Latines, and in use openly with the Arabians and Persians, because the thing itselfe first came from them…. In Persia and a certaine part of India is a certaine kinde of Goate called Pazain – the colour of this beast is commonly reddish, the height thereof indifferent – in whose stomack concretes the stone called Bezoar.

Photo by Jacob Spencer on Unsplash

It growes by little and little about a straw or some such like substance in scailes, like to the scailes of an onion. So that, when as the first scaile is taken off, the next appears more smooth and shining as you still take them away — the which amongst others is the sign of good Bezoar and not adulterate. This stone is found in sundry shapes, but commonly it resembles an Acorne or Date-stone. It is sometimes of a sanguine colour, and otherwhiles of a honey-like or yellowish colour, but most frequently of a blackish or dark greene, resembling the colour of mad Apples [aubergines], or else of a Civet Cat. This stone hath no heart nor kernel in the midst, but powder in the cavity thereof, which is also of the same faculty [i.e. efficacy].’

Paré’s etymology is largely correct. The Shorter Oxford Englsih Dictionary (OED) records ‘Bezoar… 1477… adaptation of Persian pād-zahr counter-poison’. So Bezoar turns out to be a calculus or concretion formed in the intestines of Persian goats. Hmm, I see. But, at least, in contrast to Theriac and Mithridatium, it does not contain dozens of obscure and expensive ‘simples’ compounded in a secretive manner.

Preparation and Prescription: ‘By much exceeds what other Antidotes soever’

And so, setting aside for a moment the sourcing of such an exotic object, how is Bezoar to be used, and what is it good for?

‘Now this stone is light, & not very hard, but such that it may easily be scraped, or rasped like alabaster, so that it will dissolve, being long macerated in water…. They [the Persians] use it, induced thereto by our example, not onely against poysons, but also against the bites of venomous beasts….’ According to one authority, Paré continues, it may be used ‘with very good successe in inveterate melancholy2 diseases [such] as the itch, scab, tetters3 & leprosie; therefore, by the same reason, it may well be given against a quartaine feaver.’ Furthermore, Bezoar powder, if applied ‘to pestilent Carbuncles when they are opened, it drawes forth the venome’; and it is good for ‘the small pocks and meazles… two grains each day in Rose water’. To sum up, some authorities believed ‘that this stone by much exceeds not only other simple medicines of this kind, but also such as are termed theriacalia, and what other Antidotes soever.’

Albrecht Dürer  (1471–1528), Melencholia (Minneapolis Institute of Art)

Caveat emptor: Trade restrictions, authenticity and efficacy

It is not surprising, then, that the authorities in Persia should have taken steps to protect this valuable resource. ‘At first,’ explains Paré, ‘it was common amongst us [in Western Europe], and of no very great price, because our people who trafficked in Persia, bought it at an easie rate. But after that the faculties thereof were found out, it began to be counted more rare and deare, and it was prohibited by an Edict from the King of that country, that nobody should sell a Goate to the stranger Merchants, unlesse he first killed him’ – i.e. the Goate, I think –  ‘and tooke forth the stone, & brought it to the King.’

As a result of these restrictions – or was it all just clever marketing? – Bezoar stones became highly sought after, finding their way into elite ‘cabinets of curiosities’ – such, indeed, as the elaborate ‘Studiolo’ belonging to Duke Francesco.

Mounted Bezoar stones in the treasure chamber of the Wittelsbach family, Kings of Bavaria. By Schtone – Own work, CC BY-SA 3.0,

Even without alleged obstacles to free trade, however, the temptation to counterfeit such a mundane and variable pebble must have been considerable. Paré is aware of the problem: ‘Of the notes by which this stone is tried [tested], (for there are many counterfeits brought hither,) the first is already declared’ – i.e. its onion-skin structure – ‘the other is, it may be blown up by the breath, like an oxes hide; for if the wind break through, and do not stay in the density thereof, it is accounted counterfeit.’ Hmm, again.4

Despite such caution in regard to authenticity, and despite his track-record of thoughtful scepticism, Paré shows little inclination to doubt the efficacy of a genuine Bezoar. At most, he doubted its universal efficacy as an antidote to all poisons. Thus:

‘Some years agoe a certaine Gentleman, who had one of these stones which he brought out of Spaine, bragged before King Charles [IX of France (1560-74)]… of the most certaine efficacie of this stone against all manner of poysons. Then the King asked of me, whether there were any Antidote which was equally and in like manner prevalent against all poisons. I answered, that nature could not admit it, for neither have all poysons the like effects, neither doe they arise from one cause; for some worke from an occult and specific property of their whole nature, others from some elementary quality that is predominant’ and so on.

That was the theory, at least. But either way, Paré suggested to the King, ‘it was an easie matter to make trial hereof….’

A trial of Bezoar

WARNING: there follows historical material some people might find distressing. I certainly do.

Paré’s ‘easie’ suggestion was to do an experiment ‘on such as were condemned to be hanged.’ (You might think that the test could more reasonably have been conducted on the ‘certaine Gentleman’ from Spain, but no matter.) ‘The motion [i.e. Paré ’s proposal] pleased the King.’

And so, forthwith, ‘There was a Cooke brought by the Jailor, who was to have been hanged within a while after for stealing two silver dishes out of his master’s house. Yet the King desired first to know of him, whether he would take the poison on this condition: that if the Antidote which was predicated to have singular power against all manner of poisons, which should be presently [i.e. immediately] given him after the poison, should free him from death, that then he should have his life saved. The Cook answered cheerfully, that he was willing to undergo the hazzard, yea, and greater matters, not only for to save his life, but to shun the infamy of the death he was like to be adjudged to.

‘Therefore he then had poison given him by the Apothecarie that then waited [upon the King] and, presently after the poison, some of the Bezahar brought from Spain. Which being taken down, within a while after he began to vomit, and to void much stoole with grievous torments, and to cry out that his inward parts were burnt with fire. Wherefore, being thirsty, and desiring water, they gave it him.

‘An hour after, with the good leave of the Jailor, I was admitted to him. I find him on the ground going like a beast upon hands and feet, with his tongue thrust forth of his mouth, his eyes fiery, vomiting, with store of cold sweats, and lastly the blood flowing forth by his ears, nose, mouth, fundament and yard. I gave him eight ounces of oile to drinke, but it did him no good, for it came too late. Wherefore at length he died with great torment and exclamation, the seventh hour from the time that he tooke the poison being scarcely passed.’


Paré had first made his name as a military surgeon with the French army. Maybe his experience of treating the injured on the battlefield had inured him to suffering? Or maybe life was cheap and pain ubiquitous? Either way, like such other contemporary anatomists as Andreas Vesalius (1514-64), Paré was not about to miss the chance for an anatomical dissection:

‘I opened the body in the presence of the Jailor and four others, and I found the bottom of his stomacke blacke and dry, as if it had beene burnt with a Cautery. Whereby I understood he had sublimate given him; whose force the Spanish Bezahar could not represse. Wherefore the King commanded to burne it.’

Sublimate, also known as ‘corrosive sublimate’, is a chloride of mercury. In suitably dilute form it does have antiseptic and disinfectant properties. In any quantity, however, it is extremely poisonous. In the very next chapter ‘Of Minerall Poysons’, Paré describes the syptoms of poisoning by sublimate: ‘Such as have taken sublimate, their tongue and jawes become straightened and rough, as if they drunke the juice of unripe services…. As soone as it descends to the stomack, it sticketh to it. Therefore presently after it frets and exulcerates; it causeth unquenchable thirst, and unexplicable torments… as if they were seared with an hot iron….’

But let’s end on a lighter note. Fractionally. According to Emsley (p.41), at much the same time in Germany, another condemned criminal took the same gamble – and lived. He, however, had had the good sense, or good fortune, to put his trust in the medicinal clay known as terra sigillata.

Sources and Reading

Paré, Ambroise. The works of that famous chirurgion Ambrose Parey translated out of Latine by Th. Johnson (London, 1634).

Emsley, John. The Elements of Murder. A History of Poison (Oxford, 2005)

(This article is a slightly edited version of my recent guest post on Mary Anne Yarde’s excellent Myths, Legends, Books and Coffee Pots site.)

  1. Book scan, Public Domain,
  2. ‘Melancholy’ was one of the four ‘humours’ whose balance determined the health of the human body. Thus there was a wide range of superficially unconnected diseases that would be described as ‘melancholic’, quite apart from depression.
  3. i.e. eczema, herpes, impetigo, etc.
  4. The law of caveat emptor, i.e. ‘buyer beware’, was first articulated in the law-suit Chandelor v Lopus in England in 1603 concerning a fake Bezoar stone.