Ambroise Paré (c.1510 – 90) was an innovative barber-surgeon, who became chief surgeon to the kings of France. His collected works, first published in 1582, discuss a wide range of surgical problems, including the treatment of hernia, ‘wounds made by Gunshot, [and] other fierie Engines’, amputations and cataracts.

Master John Banister delivering an anatomical lecture at the Barber-Surgeons’ Hall, Monkwell Street, London. c. 1580

But Paré also discusses poisons. Galileo and his new friend, Professor Girolamo Mercuriale (of whom more anon), argue about poison in my historical crime novel Galileo’s Revenge, ch.3.6, quoting the writings of Paré.


  • Concerning Poysons, &c
  • Paré and poisons
  • Of Mushromes
  • The excrementitious phlegm of the earth
  • Sources and reading

Concerning Poysons, &c

In the sixteenth-century fear of poisoning, especially amongst the rich and powerful, was widespread. Unexpected or particularly (in)convenient deaths were often attributed to poison. The joint deaths of the Grand Duke Francesco de’ Medici and his Duchess Bianca – the initiating incident of Galileo’s Revenge – were regarded as highly suspicious.

Such concerns generated a thriving medical literature on poisons and, most especially, on antidotes to poison. 1 Duke Francesco de’ Medici, and his father Cosimo before him, both devoted considerable time in their alchemical laboratories to the study of poison. It isn’t surprising, therefore, that Galileo finds some works on the subject in Francesco’s book chest.

Thus Galileo finds therein not only Mercuriale’s own recent (1582) De venenis (On poisons), but also the similarly titled and hot-off-the-press De venenis et antidotis (On poisons and antidotes) (Rome, 1586) of Andrea Baccio. Like Mercuriale, Baccio was a very successful medical doctor, becoming physician to the somewhat confusingly named Pope Sixtus V (1585-90). His expertise on poison may have helped him land this job, but so may his other works on gems, wine and mineral baths. Or maybe it was his denial that ‘the maiden fed on poison would have poisoned Alexander the Great, had he lain with her’. Anyhow, I shall return to Mercuriale and his colleagues at a later date.

For now I want to focus on Ambroise Paré.

Paré and poisons

Paré tackles poisons in Book 21 of his collected works, which book is reasonably enough entitled ‘Concerning Poysons’. He writes

  • ‘Of the poysons that come from living creatures’, including ch.34 ‘Of the Poyson of Cats’, in which he describes a clear case of allergic reaction;
  • ‘Of certaine poisonous Plants’ (ch.35), including ‘the Sardonian 2 herb’ (otherwise known as ‘marsh crowfoote or speare-wort’), Monkshood, deadly Nightshade, henbane, Colchicum or ‘meadow saffron’, Mandrage (i.e. mandrake), Opium, Hemlock, Aconite and Yew;
  • ‘Of bezoar’ (ch.36), which was a rather dubious universal panacea and antidote, to which I shall return in another post; and finally
  • ‘Of Minerall Poysons’ (ch.37), such as ‘arsenicke, sublimate [of mercury], plaister, cerusse [white lead], litharge, verdegreace, orpiment [sulphide of arsenic], filings of iron, brasse, the load-stone, lime and the like.’

Of Mushromes

In Paré ’s chapter on poisonous plants, there is also a paragraph on the dangers of mushrooms. It is this text in particular that Mercuriale quotes to Galileo. I cannot resist reproducing it in full, in the English translation published in 1634.3 PLEASE NOTE: THIS IS IN NO WAY A RELIABLE GUIDE TO THE EDIBILITY OR OTHERWISE OF MUSHROOMS, NOR TO WAYS OF RENDERING THEM EDIBLE. This is definitely not an occasion for historical re-enactment. Anyhow:

Photo by Jen Theodore on Unsplash

‘Of Mushromes, some are deadly and hurtfull of their owne kinde and nature, [such] as those which, broken, presently become of divers colours, and forthwith putrefie. Such (as Avicen saith) those are which be found of a grayish or blewish colour. Others though not hurtfull in qualitie, yet eaten in greater measure than is fitting, become deadly. For, seeing by nature they are very cold and moist and consequently abound with no small viscosity –  as [they  are] the excrementitious phlegme of the earth4 or trees whereon they grow – [so] they suffocate and extinguish the heat of the body, as [if it were] overcome by their quantity, and strangle as if one were hanged, and lastly killed.

‘Verily I cannot chuse, but pittying Gourmandizers, who though they know that Mushromes are the seminary and gate of death, yet doe they with a great deal of doo5 most greedily devoure them. I say, pitying them, [that] I will shew them and teach them the art, how they may feed upon this so much desired dish, without the endangering of their health. Know therefore that Mushromes may be eaten without danger, if that they be first boyled with wild peares; but, if you have no wilde peares, you may supply that defect with others which are the most harsh, either newly gathered, of dryed in the sun.’


‘The leaves, as also the bark of the same Tree, are good, especially of the wild, for peares are their Antidote. Yet Conciliator [i.e. Pietro d’Abano] gives another [antidote], to wit, Garlick eaten crude. Whereto in like sort vinegar may bee fitly added, so [as] to cut and attenuate the tough, viscous and grosse humors, heaped up, and in danger to strangle one by the too plentiful eating of Mushromes, as it is delivered by Galen.’

The excrementitious phlegm of the earth

The gist of Paré’s argument is that some mushrooms are intrinsically poisonous (‘of their owe kinde’), whereas others are only bad for you if consumed in excess. He explains their toxicity in terms of the Aristotelian theory of the four Elements – i.e. Earth, Water, Air and Fire. These Elements are defined by paired combinations of the four fundamental qualities, namely, hot and cold, and wet and dry. The four Elements in the world at large correspond to the four temperaments or Humours that regulate the human body, namely, Melancholic, Phlegmatic, Sanguine and Choleric. Water and Phlegm, for example, are both characterized as cold and wet. And mushrooms, being somehow the phlegm of the earth or trees upon which they grow, are very cold and wet, and therefore suppress the natural heat of the healthy human body.

It is probably just as well that most mushrooms would have been collected and marketed by ignorant country-folk like Niccolò the Gardener (see Galileo’s Revenge, ch.4.3).

Sources and reading

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

The Apologie and Treatise of Ambroise Paré, containing the voyages made into divers places, with many of his writings upon surgery. Edited and with an introduction by Geoffrey Keynes (London, 1951). This contains a very useful bibliography for further study. However, it doesn’t include most of Paré’s writings on poisons.

Lynn Thorndike, A History of Magic and Experimental Science, vols.V and VI: ‘The Sixteenth Century’ (New York, 1941).

  1. See, for example, Lynn Thorndike’s wonderful History of Magic and Experimental Science (vol.V, ch.xxi ‘Poisons, fascination and hydrophobia’).
  2. i.e. ‘sardonic’, and possibly also ‘Sardinian’.
  3. Mostly I keep the original spelling and Typography, because I love it, but I have changed some of the punctuation to make for easier reading.
  4. Not actually one of Shakespeare’s insults.
  5. No, no, not what you fear. According to the OED, ‘do’ (1586) = ‘stir, fuss’; as in ‘Much Ado About Nothing’.