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During the medieval period it was widely believed that toads had a jewel embedded in their heads, with the power to detect and counteract poisons, heal bites and stings, and help women in childbirth.[1]
The belief in the power of the toadstone is an example of similia similibus curantur, “like cures like”. Frogs and toads produce toxins from specialised glands beneath their skin, thus the stones from these animals could be effective in the treatment of poisons by sympathetic magicBasis of all magic according to the anthropologist and folklorist Sir James George Frazer, founded on the idea that things act on each other because they are linked by invisible and secret bonds..[2]
The traditional way to obtain a toadstone was to bury a toad in a pot in an anthill for the ants to eat, until only the bones and the stone were left.[1] But in reality toadstones are the fossilised remains of the teeth of Scheenstia, an extinct genus of ray-finned fish found throughout north-west Europe from the Jurassic and Cretaceous periods.[2]