Toadstone
Bufonites, borax of the jewellers
- Known today as
- Fossil teeth of an extinct fish, Lepidotes, believed to come from a toad’s head.
- Kind
- Mineral, in 1 older authority
- Constituents
- fossil fish teeth, calcium phosphate
- Earliest authority here
- Shakespeare (1564–1616)
- In other databases
- GBIF search · Wikidata search
Toadstone: what was it used for?
An antidote: set in rings, it was thought to grow hot or change color in the presence of poison.
Toadstone: what does modern science say?
No effect; a fossil.
Pharmacognosy & Toxicology
- Constituents
- fossil fish teethof the Jurassic ray-finned fish Lepidotes, the button-shaped palatal teeth
- calcium phosphate ChEMBL
- Mechanism
- A fossil tooth set in a ring, which neither heats nor changes colour near poison, and detects none. The identification was made by Robert Plot in 1677 and the trade continued regardless.
- Toxic dose
- Inert.
- Standing
- A curiosity of the cabinet; the rings survive in museums.
- Duffin, C. J. (2008). “Fossils as drugs: pharmaceutical palaeontology.” Ferrantia 54. Not indexed
Constituent names open the compound’s record at PubChem, and “ChEMBL” beside a name opens its record at ChEMBL, the European Bioinformatics Institute’s database of bioactive molecules. Where a mechanism line was checked against ChEMBL (ChEMBL 37, read 1 October 2026), the check is shown with the measured value and its source paper, or says plainly that nothing has been measured. Doses are as the references give them, for description only; this is not medical advice. Each source carries the result of its check against Crossref, PubMed, or the authority’s page: see Verification.
What Medicine Makes of It
- The Universal AntidoteBezoar, unicorn, and theriac against every poison, and what replaced them.
Toadstone: what did the older authorities say?
- Shakespeare
- “Sweet are the uses of adversity, / Which, like the toad, ugly and venomous, / Wears yet a precious jewel in his head.”
Sources
- Shakespeare, As You Like It II.1. Verified against its record · doi:10.1093/oseo/instance.00005809
Verification
- Checked
- October 1, 2026
- Passes
- Every sentence read against its sources, in the pass over the remaining 343 entries
- The Standing line checked against the authority it names (EMA, WHO, FDA, CITES, Commission E)
- Every dated or regulatory claim checked by category across the database
- Sources
- 2 cited: 1 verified against its record, 1 not indexed.
- Corrections
- None were needed.
What was checked, how, and what was found is set out on the Verification page. A checked source is one whose record was found; it does not make the entry medical advice.
Cite This Entry
Version 1 · first published September 25, 2026
- Chicago
“Toadstone.” In Materia Medica, edited by B. C. P. Statema. Version 1. The Thinking Press, 2026–. Last modified September 25, 2026. https://thethinkingpress.org/materia-medica/toadstone.
- MLA
“Toadstone.” Materia Medica, edited by B. C. P. Statema, version 1, The Thinking Press, 25 Sept. 2026, thethinkingpress.org/materia-medica/toadstone. Accessed 8 Oct. 2026.
- APA
Toadstone. (2026, September 25). In B. C. P. Statema (Ed.), Materia medica (Version 1). The Thinking Press. Retrieved October 8, 2026, from https://thethinkingpress.org/materia-medica/toadstone
Club members keep entries on a shelf with private notes, print the plates as cards, and receive an entry by email each week. Create a free account before January 1, 2027 and all of it is yours for good. About the Club
See Also
Sharing calcium phosphate
Drawing on the same sources: Shakespeare, Duffin
Caraway broth · Toad · Chamomile · Confection of hyacinth · The precious stones · the bibliography →
Nearby in the alphabet
Tobacco (Nicotiana tabacum) · Toadflax (Linaria vulgaris) · Tongue stones (called tongue-stones, and by the Germans adders’ tongues) · Tormentil · Tinder fungus (A hoof-shaped bracket of birch and beech) · Touch-pieces · Thyme (T)
Historical description, not medical advice.