For centuries, scholars believed that something as ordinary as garlic could weaken the mysterious power of a magnet. The strange claim survived from antiquity through the Middle Ages and beyond, revealing how natural knowledge could be transmitted, tested and transformed over time.
By Lorris Chevalier
For many centuries, learned authors maintained that garlic could weaken or even destroy the attractive power of a magnet. Although this claim appears implausible from a modern scientific perspective, it was repeatedly transmitted from antiquity through the medieval and early-modern periods. The relationship between garlic and the magnet was discussed in works of natural philosophy, medicine, mineralogy, natural magic, theology, and literature. Some authors merely repeated the traditional claim, while others attempted to explain it, refute it experimentally, or employ it as an analogy for entirely different phenomena.
The persistence of this belief raises several historical questions. How did the association between garlic and the magnet originate? Why did medieval and early-modern scholars continue to accept it? Why did some authors attempt to provide natural-philosophical explanations for an effect that others had already rejected? Finally, why did the relationship between garlic and magnetism remain rhetorically useful even after experimental evidence increasingly challenged its physical reality?
The history of this belief suggests that its longevity cannot be explained by a single factor. Its survival depended upon the interaction of textual transmission, reliance on ancient authorities, medieval theories of natural powers, experimental practices, and the extensive use of magnetic attraction as an analogy. The belief may have originated, at least in part, through a textual misunderstanding, but it subsequently developed an intellectual life of its own.
The Ancient Origins of the Belief
Plutarch in the Nuremberg Chronicle
The earliest clear surviving reference to the supposed power of garlic to interfere with magnetism appears in Plutarch’s Convivial Questions, composed around the beginning of the second century AD. Plutarch discusses the magnet and garlic in the context of what ancient thinkers understood as “sympathy and antipathy”. These concepts were used to describe relationships between natural substances: some bodies were believed to attract one another, while others could prevent, weaken, or reverse the powers of another substance.
Magnetic attraction was particularly suitable for this type of explanation. The magnet’s ability to attract iron was regarded as an extraordinary natural power, and its apparent vulnerability to another substance could therefore serve as an example of antipathy. In this intellectual context, the relationship between garlic and the magnet did not necessarily require a detailed causal explanation. It could simply be presented as one of many remarkable relationships existing within the natural world.
The belief appears in several ancient and late antique sources, including Plutarch and Ptolemy. It is significant, however, that these authors did not necessarily describe the phenomenon in precisely the same manner. Some sources state that garlic prevents magnetic attraction, while later traditions appear to suggest that it could cause the magnet to repel iron. These differences are important because they indicate that the belief was not transmitted as a single, stable proposition but was repeatedly reinterpreted.
Pliny and the Possible Textual Origin
Pliny in the Nuremberg Chronicle
One of the most intriguing explanations for the emergence of the belief concerns a possible textual corruption or misreading in Pliny’s Natural History. In one passage, Pliny describes the relationship between magnetic attraction and repulsion, writing that “the magnet attracts iron and another [stone] drives it away from it”. The Latin word alio, meaning “another”, could potentially be confused with allio, meaning “garlic”.
The difference is extremely small but conceptually significant. If alio is read correctly, Pliny is referring to another type of stone capable of repelling iron. If it is read as allio, the passage can instead be understood as claiming that garlic interferes with the magnet’s attraction:
the magnet attracts iron and through garlic [the magnet] drives [the iron] away from [the magnet].
This possible textual confusion provides a plausible explanation for the development of the tradition. It cannot, however, be established with complete certainty that the belief originated in this way. The chronological evidence is complicated by the fact that Plutarch’s discussion of garlic and the magnet predates the surviving medieval textual witnesses that might connect the belief directly to Pliny.
The Geoponica, a Byzantine compilation completed in the 10th century, is particularly important in this respect. It states:
The magnet, or sideritis, attracts iron; but it is divested of this power [or: it repels], when rubbed with garlic. It recovers its power, if the blood of a goat is poured upon it.
This passage combines several elements that are significant for the later history of the belief. Garlic is associated not merely with the interruption of magnetic attraction but potentially with repulsion, while goat’s blood is presented as a substance capable of restoring the magnet’s power. The passage may therefore preserve a tradition in which several different ancient accounts of natural antipathies had become combined.
The precise textual origin of the belief consequently remains uncertain. Nevertheless, the possibility of a mistaken reading of Pliny is historically significant because it demonstrates how a minor philological variation could contribute to the emergence of a new natural “fact”. Once such a claim entered the textual tradition, subsequent authors could reproduce it without necessarily being aware of its original context.
The Medieval Transmission of the Belief
A lodestone – photo by Teravolt (talk) / Wikimedia Commons
During the Middle Ages, the relationship between garlic and the magnet was frequently transmitted through works concerned with stones, plants, medicine, and natural philosophy. Many authors repeated the claim as one of the established properties of either garlic or the magnet. Such repetitions were often not based on personal observation but on the authority of earlier texts.
This mode of transmission is particularly important for understanding medieval natural philosophy. Medieval scholars did not necessarily regard every inherited statement as something that had to be independently tested. Ancient and authoritative texts constituted an important source of knowledge about the natural world. Consequently, an observation attributed to an ancient author could continue to circulate even when later readers had never personally witnessed the phenomenon.
Nevertheless, medieval natural philosophers did not always accept the belief without reflection. Averroes, for example, referred to the relationship between garlic and the magnet in his discussion of attraction. He argued that the conditions necessary for attraction could be altered, suggesting that garlic affected the material constitution of the magnet:
the composition of the magnet is changed (complexio magnetis transmutatur).
The physician Pietro Torrigiano de Torrigiani similarly maintained that the form or composition of garlic prevented iron from moving towards the magnet. These interpretations are significant because they show that the belief could be incorporated into a rational natural-philosophical framework. It was not necessarily regarded as magical or supernatural. Instead, it could be understood as an unusual but natural interaction between physical substances.
Pietro d’Abano, however, provides evidence of a more critical attitude. He reported that he had been unable to observe the supposed effect himself, except under a particular condition:
unless, perhaps, the magnet is laid in goat’s blood for an entire day.
This qualification is revealing. Rather than simply rejecting the traditional account, Pietro d’Abano preserved the possibility that the phenomenon might occur under circumstances different from those of his own experience. The authority of inherited knowledge and the evidence of personal observation could therefore coexist, even when they appeared to conflict.
Natural-Philosophical Explanations
William Gilbert demonstrating the magnet before Queen Elizabeth, 1598. Oil painting by Ernest Board in the 19th century
From the medieval period into the early modern period, several authors attempted to explain why garlic might interfere with magnetic attraction. These explanations reflected the scientific and philosophical frameworks available to them.
Some writers attributed the effect to the qualities or “temperament” of garlic. Others suggested that the particular kind of garlic or magnet might determine whether the phenomenon occurred. This allowed authors to reconcile contradictory evidence: if an experiment failed to reproduce the traditional effect, the problem could be attributed to differences in the substances used.
Other explanations drew upon contemporary theories of matter. Lucilio Vanini, for example, interpreted magnetic attraction through the emission of a form or spirit that travelled between the magnet and iron. Garlic could supposedly interfere with this process. Alessandro Vicentini similarly rejected the idea that magnetism was simply an “occult quality” and instead connected it with the physical temperament of the magnet.
A more explicitly mechanical explanation was later offered by Robert Midgley:
Also there may be a reason given why the Load-stone being rubbed with Garlick, or Oyle, doth not so easily draw Iron to it, especially if you also rub them with it; because these strange corpuscles by their Oyliness do hinder the emission of the corpuscles out of the Load-stone, and also their entrance into the Pores of the Iron, and do break their elastick force.
Here the supposed effect is explained through corpuscles and their movement. Garlic is imagined to interfere physically with the transmission of magnetic power. The passage illustrates the extent to which the traditional belief could be adapted to new theories of matter rather than simply disappearing when older philosophical frameworks were challenged.
Experimental Refutation
Harvesting garlic, from Tacuinum Sanitatis, ca. 1400 (Bibliothèque nationale, Paris).
The sixteenth century witnessed an increasing interest in direct observation and experiment, and this gradually transformed the status of the belief. Authors such as Gerolamo Cardano and Antoine Mizauld challenged the supposed effect on the basis of experience. Michele Mercati dismissed the claim that garlic could interfere with magnetic instruments as a seaman’s tale, arguing that such stories survived because authors carelessly copied earlier authorities.
The work of Della Porta illustrates the complexity of this transition. He eventually discussed experimental evidence against the supposed effect, yet elsewhere in his writings he continued to mention the traditional relationship between garlic and the magnet. This apparent contradiction demonstrates that the rejection of a traditional belief was not necessarily immediate or consistent.
The same problem can be observed in Bernardo Cesi. In one context, he accepted the experimental rejection of the traditional claim; elsewhere, he referred to the supposed effect as an established example. Such inconsistencies suggest that authors did not always treat inherited statements in the same way throughout their works.
The process of experimental refutation therefore did not simply replace an old belief with a new one. Instead, the old claim continued to circulate alongside its rejection. An author might reject the physical phenomenon when discussing magnetism directly but still employ it elsewhere as an example or analogy.
The Use of the Magnet as an Analogy
The survival of the belief can be explained partly by the importance of the magnet as a source of analogies. Magnetic attraction was frequently used to illustrate abstract concepts such as attraction, action at a distance, hidden powers, and the interaction between different substances.
The relationship between garlic and the magnet was particularly useful because it represented a simple conceptual structure: one substance possesses a natural power, while another substance can interfere with that power. This relationship could be transferred into many different intellectual contexts.
In medieval medicine, magnetic attraction was used to explain the attraction of nourishment by bodily organs. Jean Fernel also employed the magnet as an analogy for the human soul, arguing that a single substance could possess different powers. The supposed ability of garlic to weaken magnetic attraction could then illustrate how a natural faculty might be obstructed or lost.
The analogy was also employed in religious writing. Johann Mathesius, for example, compared Christ to a magnet attracting the hearts of Christians. Sin and other spiritual dangers were represented as substances that could interfere with this attraction:
“If the hearts are restive and anointed with Egypt garlic and Roman onions, and Turkish ‘maschlach,’ or covered with rust and sins against the conscience, our magnet [Christ] will not accept the heart.”
In this context, the physical truth of the claim was less important than its rhetorical usefulness. The supposed interaction between garlic and the magnet provided a vivid image through which an abstract theological argument could be communicated.
The longevity of the belief that garlic could weaken a magnet reflects the complex ways in which natural knowledge was transmitted and transformed. Ancient authorities such as Plutarch and Pliny were highly influential, while the claim could also be accommodated within medieval and early-modern theories of natural powers, including ideas of sympathy, antipathy, temperament, and material composition. As the magnet was rarely studied in isolation, the belief remained embedded in a wider intellectual framework and was frequently used as an analogy in medicine, theology, astrology, and natural philosophy.
Although the belief may have originated, at least in part, from a textual misunderstanding involving alio and allio, it acquired a life of its own through repeated transmission and interpretation. Even when early-modern experiments increasingly challenged its physical reality, the claim continued to circulate because of its explanatory and rhetorical value. The history of garlic and the magnet therefore demonstrates that the development of scientific knowledge was not a simple progression from error to truth, but a complex process shaped by textual transmission, authority, philosophical reasoning, experiment, and analogy. It also highlights the importance of philological analysis in understanding how seemingly minor textual ambiguities can contribute to the formation and persistence of natural knowledge.
Dr Lorris Chevalier, who has a Ph.D. in medieval literature, is a historical advisor for movies, including The Last Duel and Napoleon. Click here to view his website.
For centuries, scholars believed that something as ordinary as garlic could weaken the mysterious power of a magnet. The strange claim survived from antiquity through the Middle Ages and beyond, revealing how natural knowledge could be transmitted, tested and transformed over time.
By Lorris Chevalier
For many centuries, learned authors maintained that garlic could weaken or even destroy the attractive power of a magnet. Although this claim appears implausible from a modern scientific perspective, it was repeatedly transmitted from antiquity through the medieval and early-modern periods. The relationship between garlic and the magnet was discussed in works of natural philosophy, medicine, mineralogy, natural magic, theology, and literature. Some authors merely repeated the traditional claim, while others attempted to explain it, refute it experimentally, or employ it as an analogy for entirely different phenomena.
The persistence of this belief raises several historical questions. How did the association between garlic and the magnet originate? Why did medieval and early-modern scholars continue to accept it? Why did some authors attempt to provide natural-philosophical explanations for an effect that others had already rejected? Finally, why did the relationship between garlic and magnetism remain rhetorically useful even after experimental evidence increasingly challenged its physical reality?
The history of this belief suggests that its longevity cannot be explained by a single factor. Its survival depended upon the interaction of textual transmission, reliance on ancient authorities, medieval theories of natural powers, experimental practices, and the extensive use of magnetic attraction as an analogy. The belief may have originated, at least in part, through a textual misunderstanding, but it subsequently developed an intellectual life of its own.
The Ancient Origins of the Belief
The earliest clear surviving reference to the supposed power of garlic to interfere with magnetism appears in Plutarch’s Convivial Questions, composed around the beginning of the second century AD. Plutarch discusses the magnet and garlic in the context of what ancient thinkers understood as “sympathy and antipathy”. These concepts were used to describe relationships between natural substances: some bodies were believed to attract one another, while others could prevent, weaken, or reverse the powers of another substance.
Magnetic attraction was particularly suitable for this type of explanation. The magnet’s ability to attract iron was regarded as an extraordinary natural power, and its apparent vulnerability to another substance could therefore serve as an example of antipathy. In this intellectual context, the relationship between garlic and the magnet did not necessarily require a detailed causal explanation. It could simply be presented as one of many remarkable relationships existing within the natural world.
The belief appears in several ancient and late antique sources, including Plutarch and Ptolemy. It is significant, however, that these authors did not necessarily describe the phenomenon in precisely the same manner. Some sources state that garlic prevents magnetic attraction, while later traditions appear to suggest that it could cause the magnet to repel iron. These differences are important because they indicate that the belief was not transmitted as a single, stable proposition but was repeatedly reinterpreted.
Pliny and the Possible Textual Origin
One of the most intriguing explanations for the emergence of the belief concerns a possible textual corruption or misreading in Pliny’s Natural History. In one passage, Pliny describes the relationship between magnetic attraction and repulsion, writing that “the magnet attracts iron and another [stone] drives it away from it”. The Latin word alio, meaning “another”, could potentially be confused with allio, meaning “garlic”.
The difference is extremely small but conceptually significant. If alio is read correctly, Pliny is referring to another type of stone capable of repelling iron. If it is read as allio, the passage can instead be understood as claiming that garlic interferes with the magnet’s attraction:
the magnet attracts iron and through garlic [the magnet] drives [the iron] away from [the magnet].
This possible textual confusion provides a plausible explanation for the development of the tradition. It cannot, however, be established with complete certainty that the belief originated in this way. The chronological evidence is complicated by the fact that Plutarch’s discussion of garlic and the magnet predates the surviving medieval textual witnesses that might connect the belief directly to Pliny.
The Geoponica, a Byzantine compilation completed in the 10th century, is particularly important in this respect. It states:
The magnet, or sideritis, attracts iron; but it is divested of this power [or: it repels], when rubbed with garlic. It recovers its power, if the blood of a goat is poured upon it.
This passage combines several elements that are significant for the later history of the belief. Garlic is associated not merely with the interruption of magnetic attraction but potentially with repulsion, while goat’s blood is presented as a substance capable of restoring the magnet’s power. The passage may therefore preserve a tradition in which several different ancient accounts of natural antipathies had become combined.
The precise textual origin of the belief consequently remains uncertain. Nevertheless, the possibility of a mistaken reading of Pliny is historically significant because it demonstrates how a minor philological variation could contribute to the emergence of a new natural “fact”. Once such a claim entered the textual tradition, subsequent authors could reproduce it without necessarily being aware of its original context.
The Medieval Transmission of the Belief
During the Middle Ages, the relationship between garlic and the magnet was frequently transmitted through works concerned with stones, plants, medicine, and natural philosophy. Many authors repeated the claim as one of the established properties of either garlic or the magnet. Such repetitions were often not based on personal observation but on the authority of earlier texts.
This mode of transmission is particularly important for understanding medieval natural philosophy. Medieval scholars did not necessarily regard every inherited statement as something that had to be independently tested. Ancient and authoritative texts constituted an important source of knowledge about the natural world. Consequently, an observation attributed to an ancient author could continue to circulate even when later readers had never personally witnessed the phenomenon.
Nevertheless, medieval natural philosophers did not always accept the belief without reflection. Averroes, for example, referred to the relationship between garlic and the magnet in his discussion of attraction. He argued that the conditions necessary for attraction could be altered, suggesting that garlic affected the material constitution of the magnet:
the composition of the magnet is changed (complexio magnetis transmutatur).
The physician Pietro Torrigiano de Torrigiani similarly maintained that the form or composition of garlic prevented iron from moving towards the magnet. These interpretations are significant because they show that the belief could be incorporated into a rational natural-philosophical framework. It was not necessarily regarded as magical or supernatural. Instead, it could be understood as an unusual but natural interaction between physical substances.
Pietro d’Abano, however, provides evidence of a more critical attitude. He reported that he had been unable to observe the supposed effect himself, except under a particular condition:
unless, perhaps, the magnet is laid in goat’s blood for an entire day.
This qualification is revealing. Rather than simply rejecting the traditional account, Pietro d’Abano preserved the possibility that the phenomenon might occur under circumstances different from those of his own experience. The authority of inherited knowledge and the evidence of personal observation could therefore coexist, even when they appeared to conflict.
Natural-Philosophical Explanations
From the medieval period into the early modern period, several authors attempted to explain why garlic might interfere with magnetic attraction. These explanations reflected the scientific and philosophical frameworks available to them.
Some writers attributed the effect to the qualities or “temperament” of garlic. Others suggested that the particular kind of garlic or magnet might determine whether the phenomenon occurred. This allowed authors to reconcile contradictory evidence: if an experiment failed to reproduce the traditional effect, the problem could be attributed to differences in the substances used.
Other explanations drew upon contemporary theories of matter. Lucilio Vanini, for example, interpreted magnetic attraction through the emission of a form or spirit that travelled between the magnet and iron. Garlic could supposedly interfere with this process. Alessandro Vicentini similarly rejected the idea that magnetism was simply an “occult quality” and instead connected it with the physical temperament of the magnet.
A more explicitly mechanical explanation was later offered by Robert Midgley:
Also there may be a reason given why the Load-stone being rubbed with Garlick, or Oyle, doth not so easily draw Iron to it, especially if you also rub them with it; because these strange corpuscles by their Oyliness do hinder the emission of the corpuscles out of the Load-stone, and also their entrance into the Pores of the Iron, and do break their elastick force.
Here the supposed effect is explained through corpuscles and their movement. Garlic is imagined to interfere physically with the transmission of magnetic power. The passage illustrates the extent to which the traditional belief could be adapted to new theories of matter rather than simply disappearing when older philosophical frameworks were challenged.
Experimental Refutation
The sixteenth century witnessed an increasing interest in direct observation and experiment, and this gradually transformed the status of the belief. Authors such as Gerolamo Cardano and Antoine Mizauld challenged the supposed effect on the basis of experience. Michele Mercati dismissed the claim that garlic could interfere with magnetic instruments as a seaman’s tale, arguing that such stories survived because authors carelessly copied earlier authorities.
The work of Della Porta illustrates the complexity of this transition. He eventually discussed experimental evidence against the supposed effect, yet elsewhere in his writings he continued to mention the traditional relationship between garlic and the magnet. This apparent contradiction demonstrates that the rejection of a traditional belief was not necessarily immediate or consistent.
The same problem can be observed in Bernardo Cesi. In one context, he accepted the experimental rejection of the traditional claim; elsewhere, he referred to the supposed effect as an established example. Such inconsistencies suggest that authors did not always treat inherited statements in the same way throughout their works.
The process of experimental refutation therefore did not simply replace an old belief with a new one. Instead, the old claim continued to circulate alongside its rejection. An author might reject the physical phenomenon when discussing magnetism directly but still employ it elsewhere as an example or analogy.
The Use of the Magnet as an Analogy
The survival of the belief can be explained partly by the importance of the magnet as a source of analogies. Magnetic attraction was frequently used to illustrate abstract concepts such as attraction, action at a distance, hidden powers, and the interaction between different substances.
The relationship between garlic and the magnet was particularly useful because it represented a simple conceptual structure: one substance possesses a natural power, while another substance can interfere with that power. This relationship could be transferred into many different intellectual contexts.
In medieval medicine, magnetic attraction was used to explain the attraction of nourishment by bodily organs. Jean Fernel also employed the magnet as an analogy for the human soul, arguing that a single substance could possess different powers. The supposed ability of garlic to weaken magnetic attraction could then illustrate how a natural faculty might be obstructed or lost.
The analogy was also employed in religious writing. Johann Mathesius, for example, compared Christ to a magnet attracting the hearts of Christians. Sin and other spiritual dangers were represented as substances that could interfere with this attraction:
“If the hearts are restive and anointed with Egypt garlic and Roman onions, and Turkish ‘maschlach,’ or covered with rust and sins against the conscience, our magnet [Christ] will not accept the heart.”
In this context, the physical truth of the claim was less important than its rhetorical usefulness. The supposed interaction between garlic and the magnet provided a vivid image through which an abstract theological argument could be communicated.
The longevity of the belief that garlic could weaken a magnet reflects the complex ways in which natural knowledge was transmitted and transformed. Ancient authorities such as Plutarch and Pliny were highly influential, while the claim could also be accommodated within medieval and early-modern theories of natural powers, including ideas of sympathy, antipathy, temperament, and material composition. As the magnet was rarely studied in isolation, the belief remained embedded in a wider intellectual framework and was frequently used as an analogy in medicine, theology, astrology, and natural philosophy.
Although the belief may have originated, at least in part, from a textual misunderstanding involving alio and allio, it acquired a life of its own through repeated transmission and interpretation. Even when early-modern experiments increasingly challenged its physical reality, the claim continued to circulate because of its explanatory and rhetorical value. The history of garlic and the magnet therefore demonstrates that the development of scientific knowledge was not a simple progression from error to truth, but a complex process shaped by textual transmission, authority, philosophical reasoning, experiment, and analogy. It also highlights the importance of philological analysis in understanding how seemingly minor textual ambiguities can contribute to the formation and persistence of natural knowledge.
Dr Lorris Chevalier, who has a Ph.D. in medieval literature, is a historical advisor for movies, including The Last Duel and Napoleon. Click here to view his website.
Click here to read more from Lorris Chevalier
Further Readings:
Christoph Sander, “Magnets and garlic: an enduring antipathy in early-modern science,” Intellectual History Review, 30:4 (2020)
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