"It [lye ash] is also drunk against the consumption of gypsum and the bite of the spider."

But why would consumption of relevant amounts of gypsum occur in the first place?


  • I believe that consuming too much calcium can cause symptoms like nausea, stomach pains, constipation, vomiting etc. I'm not sure how much would be "too much" though. I'd imagine it's a lot! Jul 29, 2017 at 17:59
  • @sempaiscuba Gypsum isn't calcium, but calcium suphate. Accidental consumtion of relevant quantitys doesn't seem plausible to me.
    – HannesH
    Jul 29, 2017 at 18:34
  • @DenisdeBernardy Biologists probably do not know any better why anyone would consume gypsum.
    – HannesH
    Jul 29, 2017 at 18:36
  • @DenisdeBernardy That is not my question though. I am shure that eating gypsum is a medical problem at some point (constapation...). The question is why this is any relevant - did people consume gypsum, and why so? I will edit the question for clarity.
    – HannesH
    Jul 29, 2017 at 18:45

2 Answers 2


It's likely because of presumed medical properties.

This page (in French), for instance, offers that Gypsum (called both Gypse and Albâtre in French) as a component to make skin rejuvenating creams in Ancient Egypt. There are a few sensible sources at the bottom of the page to back the claim.

This dictionary of Medical Matter from 1837 (in French) offers that sodium carbonate ("Albâtre calcaire") had been used as an absorbent against stomach pain and diarrhea, as well as against scurvy, and that gypsum proper, or calcium sulfate, had been used according to Paul of Aegina against stomach diseases. That is, IMHO, the most likely source of why it might have been absorbed for and attributed with medical properties.

In more modern times, this dictionary of medicine, surgury and pharmacy from 1834 (in French) also offers that gypsum was used to soften tumors.

I would add: don't discount hocus pocus reasons. This other page (French yet again) holds without citing a source that Gypsium (under Albâtre) has a slew of esoteric benefits, including appeasing effects, self-confidence, bone benefits, and improvements when visiting your radiologist to detect liquid elements if you happen to be hold it in a certain way. If the couple of times I interacted with people who were into would-be properties of crystals are anything to go by, there's an ages old laundry list of beliefs on mineral topics and I wouldn't be surprised the slightest if at least a few of these benefits originate from alchemy treaties, religious beliefs, obscure classical treaties, etc. that got passed on through generations after countless rounds of Chinese whispers.


Book V of the De Materia Medica itself contains the medical uses of gypsum known at that time. The (uncopyrighted) text is in German, but a google translation roughly reads:

The gypsum has astringent, a skin forming force; he stops bleeding and holds back the sweat; but enjoyed it kills the type of suffocation.

We also have historical reference of gypsum being used, with fatal results.

Pliny the Elder, The Natural History in BOOK XXXVI. THE NATURAL HISTORY OF STONES, has a section devoted to the common uses of gypsum as a plastering compound. He also reveals its dangers:

There is one remarkable fact connected with this substance; Caius Proculeius,461 an intimate friend of the Emperor Augustus, suffering from violent pains in the stomach, swallowed gypsum, and so put an end to his existence.

We can conclude gypsum was historically used, and fatal consequences were known to occur if misused. It would be only logical to also list any counter-agents, no matter how common or uncommon the need may have been. Think of it as an "in case of poisoning, use this" type of protective instruction.

  • Book V accualy describes the medical uses of gypsum as external only, while ingestion, not just exessive ingestion, is described as deadly (by way of suffocation).
    – HannesH
    Jul 31, 2017 at 0:49

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