In the Middle Ages, frogs lived at the edge of human imagination — slimy, loud, and unsettling, yet strangely indispensable. They were feared as unclean creatures linked with plague and sin, but they were also ingredients in medicine, subjects of moral fables, and symbols of transformation. In a new study published in Mediaeval Studies, Greti Dinkova-Bruun explores how the frog leapt between the worlds of healing and storytelling, showing how this humble amphibian embodied both physical and moral meaning.
Frogs appear frequently in medieval medical writings as useful ingredients. Dinkova-Bruun traces their presence in De medicamentis liber, a fifth-century collection of remedies by the Gallo-Roman physician Marcellus Empiricus. His manual catalogues hundreds of treatments from head to toe, combining herbs, animal parts, and ritual actions in equal measure. Among the many creatures pressed into service, the frog features in eleven recipes, often for ailments that were both common and mysterious: earache, ulcers, dysentery, and toothache.
Some of these cures verge on the surreal. One treatment instructs the physician to place a living frog on the patient’s stomach so that the illness might pass into the animal. Another prescribes frog bile for ulcers and frog blood for eye irritation. To relieve joint pain, the patient was told to apply crushed frogs as a poultice. The most striking example, however, is a charm for toothache:
“When the moon is waning on the day of Mars or on the day of Jupiter, say these words seven times: ARGIDAM MARGIDAM STVRGIDAM. You will eliminate the pain when, while standing in the open air, on fresh ground and wearing shoes, you grasp the head of a frog, open its mouth, spit in it, and ask it to take the toothache away with it. Then release the living [frog] and do so on a good day and at a good hour.”
Marcellus’s recipes blend practical medicine, sympathetic magic, and ritual performance. The frog, straddling land and water, life and decay, was a natural medium for the movement of illness from body to beast. The spell’s careful timing and repetition suggest a faith in cosmic order as much as in biology.
Eight centuries later, frogs and toads reappear in the encyclopedic Speculum naturale by Vincent of Beauvais. Vincent treats them not as magical partners but as medical specimens. Drawing on sources like Pliny, Avicenna, and Isidore of Seville, he lists cures in which frogs are boiled, burned, or mixed with honey, oil, and salt. Their bile removes worms, their fat eases ear pain, and their ashes stop bleeding. He even mentions a stone found in the head of the toad that acts as an antidote to poison.
Dinkova-Bruun writes
Marcellus’s medical manual and Vincent’s enormous compilation of knowledge contain two different but nevertheless complementary accounts of how the frog and the toad could be useful in curing diseases, both external and internal. Many of the recipes included in these texts (and in various others) sound outlandish or distasteful to us, but they nevertheless open a window onto the premodern understanding of the constitution of the human body with its ailments, wounds, and pains, and they describe the effects of a multitude of cures that were manufactured from every possible ingredient the medical practitioners could find not only in the natural world around them but also in the learned works of their predecessors.
Together, these two writers show how frogs were seen as part of a vast medieval pharmacology that mixed observation, faith, and inherited authority. The same creature could be a healer, a toxin, or a channel for divine power.
Frogs that Talk: Lessons from Medieval Fables
Frog in a 15th-century fable – Chantilly, Bibliothèque et archives du château, Ms. 680 (olim 1389), fol. 218r
Medieval frogs were also a frequent character in Latin fables, where they became mirrors of human folly and pride. Dinkova-Bruun compares how authors such as Alexander Neckam, “Walter of England,” and Odo of Cheriton retold the classical fables of Aesop and Phaedrus for new moral purposes.
One of the most famous tales is The Mouse and the Frog. In Neckam’s version, a timid mouse begs a frog for help crossing a river. The frog agrees, ties the mouse to her leg, and then treacherously dives underwater. Both are punished when a kite swoops down and carries them away together. The moral is simple: “Whoever betrays the one who has faith in him, is betrayed in turn; he too, as the frog, rightly dies caught in his own net.”
Other frog tales carry similar warnings. In The Frogs and the Hares, frightened animals consider leaping to their deaths until they notice that the frogs fear them even more — a lesson in courage and perspective. Another classic, The Frog and the Ox, tells of a frog so envious of an ox’s size that she swells herself up until she bursts. Odo reads it as a biting attack on ambitious churchmen who, trying to imitate bishops and abbots, destroy both body and soul. Through such fables, the frog became a stand-in for every kind of pretension, lust, or pride that medieval moralists sought to deflate.
From Pond to Pulpit
Why did frogs capture so much attention in the medieval imagination? Dinkova-Bruun suggests that they were creatures both feared and used — condemned in Scripture as unclean yet employed in medical practice as ingredients in cures. Their image carried strong moral weight: medieval authors associated them with heretics, lust, and corruption, while encyclopedists like Bartholomaeus Anglicus described them “as abominable to humankind and very odious.” At the same time, their bodies and secretions appeared in recipes to ease pain, draw out disease, and heal wounds.
Across medicine and literature, the frog served very different purposes: it could be a tool for healing in one text and a symbol of moral decay in another. Dinkova-Bruun’s study brings these worlds together, showing how a single animal could move from the pages of a physician’s manual to the verses of a moral fable. Whether treated as a physical remedy or a spiritual warning, the medieval frog occupied a distinctive place in the imagination of the age.
This examination of frogs is focused on pharmaceutical works and fables, but Dinkova-Bruun believes that much more can be learned about these amphibians in other medieval sources. She writes:
further insights could be gained through the exploration of other areas, for example, illustrated Bibles, encyclopedias, and bestiaries that provide pictorial representations of the frog, biblical commentaries that provide several noteworthy allegorical and moralistic interpretations, and exempla in sermons.
In the Middle Ages, frogs lived at the edge of human imagination — slimy, loud, and unsettling, yet strangely indispensable. They were feared as unclean creatures linked with plague and sin, but they were also ingredients in medicine, subjects of moral fables, and symbols of transformation. In a new study published in Mediaeval Studies, Greti Dinkova-Bruun explores how the frog leapt between the worlds of healing and storytelling, showing how this humble amphibian embodied both physical and moral meaning.
Frogs appear frequently in medieval medical writings as useful ingredients. Dinkova-Bruun traces their presence in De medicamentis liber, a fifth-century collection of remedies by the Gallo-Roman physician Marcellus Empiricus. His manual catalogues hundreds of treatments from head to toe, combining herbs, animal parts, and ritual actions in equal measure. Among the many creatures pressed into service, the frog features in eleven recipes, often for ailments that were both common and mysterious: earache, ulcers, dysentery, and toothache.
Some of these cures verge on the surreal. One treatment instructs the physician to place a living frog on the patient’s stomach so that the illness might pass into the animal. Another prescribes frog bile for ulcers and frog blood for eye irritation. To relieve joint pain, the patient was told to apply crushed frogs as a poultice. The most striking example, however, is a charm for toothache:
“When the moon is waning on the day of Mars or on the day of Jupiter, say these words seven times: ARGIDAM MARGIDAM STVRGIDAM. You will eliminate the pain when, while standing in the open air, on fresh ground and wearing shoes, you grasp the head of a frog, open its mouth, spit in it, and ask it to take the toothache away with it. Then release the living [frog] and do so on a good day and at a good hour.”
Marcellus’s recipes blend practical medicine, sympathetic magic, and ritual performance. The frog, straddling land and water, life and decay, was a natural medium for the movement of illness from body to beast. The spell’s careful timing and repetition suggest a faith in cosmic order as much as in biology.
Eight centuries later, frogs and toads reappear in the encyclopedic Speculum naturale by Vincent of Beauvais. Vincent treats them not as magical partners but as medical specimens. Drawing on sources like Pliny, Avicenna, and Isidore of Seville, he lists cures in which frogs are boiled, burned, or mixed with honey, oil, and salt. Their bile removes worms, their fat eases ear pain, and their ashes stop bleeding. He even mentions a stone found in the head of the toad that acts as an antidote to poison.
Dinkova-Bruun writes
Marcellus’s medical manual and Vincent’s enormous compilation of knowledge contain two different but nevertheless complementary accounts of how the frog and the toad could be useful in curing diseases, both external and internal. Many of the recipes included in these texts (and in various others) sound outlandish or distasteful to us, but they nevertheless open a window onto the premodern understanding of the constitution of the human body with its ailments, wounds, and pains, and they describe the effects of a multitude of cures that were manufactured from every possible ingredient the medical practitioners could find not only in the natural world around them but also in the learned works of their predecessors.
Together, these two writers show how frogs were seen as part of a vast medieval pharmacology that mixed observation, faith, and inherited authority. The same creature could be a healer, a toxin, or a channel for divine power.
Frogs that Talk: Lessons from Medieval Fables
Medieval frogs were also a frequent character in Latin fables, where they became mirrors of human folly and pride. Dinkova-Bruun compares how authors such as Alexander Neckam, “Walter of England,” and Odo of Cheriton retold the classical fables of Aesop and Phaedrus for new moral purposes.
One of the most famous tales is The Mouse and the Frog. In Neckam’s version, a timid mouse begs a frog for help crossing a river. The frog agrees, ties the mouse to her leg, and then treacherously dives underwater. Both are punished when a kite swoops down and carries them away together. The moral is simple: “Whoever betrays the one who has faith in him, is betrayed in turn; he too, as the frog, rightly dies caught in his own net.”
Other frog tales carry similar warnings. In The Frogs and the Hares, frightened animals consider leaping to their deaths until they notice that the frogs fear them even more — a lesson in courage and perspective. Another classic, The Frog and the Ox, tells of a frog so envious of an ox’s size that she swells herself up until she bursts. Odo reads it as a biting attack on ambitious churchmen who, trying to imitate bishops and abbots, destroy both body and soul. Through such fables, the frog became a stand-in for every kind of pretension, lust, or pride that medieval moralists sought to deflate.
From Pond to Pulpit
Why did frogs capture so much attention in the medieval imagination? Dinkova-Bruun suggests that they were creatures both feared and used — condemned in Scripture as unclean yet employed in medical practice as ingredients in cures. Their image carried strong moral weight: medieval authors associated them with heretics, lust, and corruption, while encyclopedists like Bartholomaeus Anglicus described them “as abominable to humankind and very odious.” At the same time, their bodies and secretions appeared in recipes to ease pain, draw out disease, and heal wounds.
Across medicine and literature, the frog served very different purposes: it could be a tool for healing in one text and a symbol of moral decay in another. Dinkova-Bruun’s study brings these worlds together, showing how a single animal could move from the pages of a physician’s manual to the verses of a moral fable. Whether treated as a physical remedy or a spiritual warning, the medieval frog occupied a distinctive place in the imagination of the age.
This examination of frogs is focused on pharmaceutical works and fables, but Dinkova-Bruun believes that much more can be learned about these amphibians in other medieval sources. She writes:
further insights could be gained through the exploration of other areas, for example, illustrated Bibles, encyclopedias, and bestiaries that provide pictorial representations of the frog, biblical commentaries that provide several noteworthy allegorical and moralistic interpretations, and exempla in sermons.
Greti Dinkova-Bruun’s article, “The Medieval Frog in Medical Recipes and Fable Narratives” is published in the latest issue of Mediaeval Studies – click here to order this issue. You can also access it through Greti Dinkova-Bruun’s Academia.edu page.
Greti Dinkova-Bruun is a Fellow and Library Director at the Pontifical Institute of Mediaeval Studies in Toronto.
Top Image: Montpellier. Bibliothèque interuniversitaire, Section Médecine, H 418 fol. 23
Subscribe to Medievalverse
Related Posts