Tag Archives: Poison

The dose makes the poison: dangerous plants

By Marieke Hendriksen

'The gift of chemistry', by P.H. Looff, 1773
‘The gift of chemistry’, by P.H. Looff, 1773

My current research focuses on how certain materials, particularly metals, gemstones and glass, mostly disappeared from the medicine of Boerhaave and his followers. This primarily had to do with how these substances were chemically understood. When I tell this to people, they mostly nod in agreement, assuming that Leiden professor of medicine, chemistry and botany Herman Boerhaave (1668-1738) discovered how poisonous metals are for the human body through chemical analysis, and subsequently banished them from his medicine. The truth is a little more nuanced. Boerhaave’s ideas about these substances and his idea of poisonousness were deeply influenced by those of illustrious medical men like Paracelsus (1493-1541) and the common alchemical understandings of matter at the time.

The reason that Boerhaave thought most metals were poisonous for humans for example was not because he had systematically tested the effects of ingestion, but because he argued from an alchemical understanding that the corrosive nature of most metals, except for gold and iron, meant that they were generally damaging for the human body. Only in very severe cases of otherwise incurable diseases, such as syphilis, could an appropriately cultivated preparation of a heavy metal like mercury be used as a last resource. Neither did Boerhaave’s discouragement of the use of substances such as metals in medicine mean that he thought all vegetable substances were safe to use, and he discusses vegetable poisons in his lectures.

Poisonous hemlock (Conium maculatum) Courtesy of  Kurt Stüber, www.biolib.de.
Poisonous hemlock (Conium maculatum) Courtesy of Kurt Stüber, www.biolib.de.

However, Boerhaave, although critical of Paracelsus, was also aware of the truth of his adage ‘the dose makes the poison,’ and a fervent advocate of critical thinking and practical research, who told his readers to think for themselves and undertake their own experiments. The impact of his work and attitude becomes clear from an array of eighteenth-century works on medicine, ranging from academic chemistry and medical handbooks to private recipe collections and small practical medical treatises in the vernacular. A nice example is a pamphlet by Philip Looff (1745-1778), a medical doctor from Groningen, published in 1773 under the title Donum Chemicum, literally ‘the gift of chemistry.’[1]

Rough chervil (Chaerophyllum temulentum). Couresy of Kurt Stüber, www.biolib.de.
Rough chervil (Chaerophyllum temulentum). Courtesy of Kurt Stüber, www.biolib.de.

Although Looff obviously never met Boerhaave, he dedicated his book to Boerhaave’s successor and former student H.D. Gaub (1705-1780), who endorsed it, and Looff repeatedly speaks of Boerhaave’s work admiringly in the book. Completely in Boerhaave’s line of thought too is his discussion of the medicinal use of rough chervil (‘dulle kervel’ or Chaerophyllum temulum), a slightly poisonous plant. It was often confused with hemlock  (Conium maculatum), which is said to have been the active ingredient in Socrates’ poisoned chalice. Like Boerhaave, Looff begins with a warning that any use of poisonous substances by the uniformed is extremely dangerous, and continuous to describe an observation of the usefulness of rough chervil in the cure of leprosy. According to Looff, he and his father in law, also a medical doctor, had successfully cured a woman suffering from leprosy be treating her with a very week solution of rough chervil and sarsaparilla – a handful of rough chervil and an ounce and a half of sarsaparilla boiled in 28 or 30 ounces of water for three hours. Although the patient went temporarily blind each time she took a two-ounce dose of the brew, after seven weeks of two daily doses, she was cured of her leprosy.

In hindsight it seems rather risky that Looff published his findings in the vernacular, as it is very easy to confuse rough chervil and hemlock – ingestion of only 6 to 8 leaves of fresh hemlock can be fatal. Yet however dangerous, these kinds of case studies were also essential for the study of the effects of potentially poisonous plants on the human body, and thus indirectly for the early nineteenth-century invention of isolating plant alkaloids  – the active chemical principles of plants that had been used medicinally for centuries and that we still know and use today.[2]


Plant prints: permission from Kurt Stüber, www.biolib.de


[2] Swann, John P. “The Pharmaceutical Industries.” edited by Peter J. Bowler and John V. Pickstone, The Cambridge History of Science. Volume 6: Modern Life and Earth Sciences: 126–40. (The Cambridge History of Science, 2009), p. 127-8.

A recipe fit for a king

Attalus II or III. Altes Museum, Berlin. Credit: Marcus Cyron, licensed under Creative Commons.
Attalus II or III. Altes Museum, Berlin. Credit: Marcus Cyron, licensed under Creative Commons.

By Laurence Totelin

One of my favourite characters in the history of ancient pharmacology is Attalus III, king of Pergamum (ruled from 138 to 133 BCE). As a king, he is remembered for bequeathing his small kingdom to Rome at his death. Apart from that, we know very little about his rule. Instead of focusing on his political achievements, ancient historical sources dwell on his strange hobbies. According to the historians Plutarch (first-second century CE, wrote in Greek) Justin (second century CE, wrote in Latin), after having his mother and wife killed, the king lost all interest in his physical appearance and developed a passion for gardening.  He planted highly poisonous herbs such as henbane, hemlock and hellebore in his gardens. He then sent to his friends samples of these plants, mixing their sap to that of non-poisonous plants. Tired of this, he then moved on to wax-modeling and pouring and forging bronze.

Plutarch and Justin are very negative in their presentation of these silly pastimes. For a more positive view of Attalus, one has to turn to medical and agronomic texts. The Latin agronomical writers Varro (116–27 BCE), Columella (first century CE), and the encyclopaedist Pliny the Elder (23-79 CE) list the king as a source on animals, fruit trees, crops, drugs from animals, metals and gems. Celsus (first century CE), in his work on medicine, gives a recipe for an Attalic plaster (5.19.11), which contains relatively large amounts of copper.  He does not, however, say whether that plaster had been created by the king Attalus or by a namesake:

There is the Attalic plaster for wounds. It contains: copper scales, 16 sextulae; frankincense soot, 15 sextulae; ammoniac salt, same amount; liquid turpentine resin, 25 sextulae; bull suet, same amount; vinegar, three heminae; oil, 1 sextarius.[1]

Although interesting, these Latin sources do not add more to our knowledge of Attalus. For more information, one needs to turn to Galen. The famous physician too came from Pergamum and on several occasions refers to Attalus as ‘Attalus who was king among us’, that is, king among the people of Pergamum. Galen was active several centuries after the death of the king, but he may have had access to some lost Pergamene sources. He may also have consulted the king’s lost medical works. He casts a very different light on Attalus’ experiments with dangerous plants. In a passage on another king, Mithridates VI of Pontus, he writes that:

Mithridates himself, like Attalus among us, desired to have experience of almost all simple drugs that are given against deadly substances, testing their powers on evil men who were condemned to death.[2]

Galen presents the two kings as methodic researchers in the field of pharmacology. While their method of experimentation seems abhorrent to us, Galen approves of it, as it greatly advanced knowledge of poisons and their antidotes. Galen also devotes a great part of his treatise On the Composition of Medicines according to Types I to various Attalic plasters. There is no doubt in Galen’s mind that these were created by the last king of Pergamum:

White plaster made with pepper, according to Attalus… This remedy has already been prepared many years ago by Attalus, ruling over us people of Pergamum, a man who was most studious about all sorts of remedies.[3]

Again Galen presents his fellow countryman as a serious scholar, not as a mad hatter. Who is right? Galen or the historians Plutarch and Justin? Nobody will ever know, but Attalus’ story is an excellent exercise in source criticism!


[1] Celsus, De Medicina 5.19.11. A sextula is a sixth of an ounce. An hemina is a half of a sextarius. A sextarius is roughly the equivalent of a British pint.

[2] Galen, On Antidotes 1.1 (14.2 Kühn).

[3] Galen, On the Composition of Medicines according to Types 1.13 (13.414 Kühn).

The Wonders of Unicorn Horns: Preventions and Cures for Poisoning

Johanna St John’s Book, Credit: Wellcome Library, London

In Johanna St. John’s recipe book, the mysterious “Banister’s Powder by Dr Bates” lay nestled between the equally intriguing “Mrs Archers way of makeing My Lady Kents Powder” and the beginning of the letter “R” section of St. John’s efficiently organized recipe book. There is no indication what type of recipe this “Banister’s Powder” was, besides a powder, or what it’s intended use was. Following several pages of recipes for “pox” and “pills” this “Powder” is the tail end of St. John’s letter “P” section, however, even knowing this context offers little information. An analysis of the “Banister’s Powder” ingredients suggests a link between St. John’s early modern medicinal recipes and the presence of magical beliefs associated with medicine in the early modern period.

The first three ingredients required to make the “Banister’s Powder” are: powdered Unicorn horn, east bezoars, and the “bones” of a stag’s heart. Each of these ingredients had longstanding associations with the belief they were capable of preventing or countering the effects of poisoning. To a modern eye, these appear strange items to reside alongside many complicated recipes which rely on an expansive knowledge of medicinal, rather than magical, properties. These ingredients indicate that magical beliefs remained acceptable practices among home practitioners in the early modern period. This is possibly because the science to disprove them was not advanced and medical practitioners were only beginning to be skeptical and move away from such unreliable remedies.

The prevention and cure of poisoning was a genuine concern before and throughout the early modern period. It was quite common to be bitten or stung, to consume poisonous berries, roots, or herbs, or to believe a spell had been cast by a witch (Jackson, 96). It was also common for physicians to diagnose poison as the cause when they could not determine the source of an ailment (Auble, 17). This led to the necessity for remedies to detect, prevent and cure poisoning.

Rhinoceros Horn Vessel, Credit: Wellcome Library, London


Pharmacy sign, Credit: Wellcome Library, London

Unicorn horns were actually believed to come from the mythical creature and possess its symbolic purity and strength, though they were most often a narwhal tooth or powdered rhinoceros horn. The horns were commonly powdered and used in poison antidotes or as vessels to drink from before or after ingesting poison (Jackson, 97). Unicorn horns were also believed to have properties which allowed them to detect poison (Knight, 245). In addition to being thought to detect, prevent or cure the effects of poison, the horns were also thought to strengthen your heart, relieve headaches, resist the plague and pestilence, expel measles and small pox, and cure “falling sickness” in children (Brockbank, 3) all of which were reoccurring ailments in the early modern period.


Bezoar stones were solid masses from the intestines of goats, sheep or deer that were primarily believed to detect poisons but also, in some cases thought to provide a cure if small amounts of the stone were consumed. “Oriental” or “East” Bezoars, as St. John called for, were the most valuable type which came from a Persian wild goat (Jackson, 97). It was occasionally consumed, but more commonly mounted on a chain and dipped in to drinks to nullify the effects of poison if there was any (Jackson, 97). Queen Elizabeth I reportedly kept one “sett in golde hanging at a little Bracelett … The most parte of this stone being spent” indicating the Queen mounted and consumed her stone (Auble, 18).

Mounted Bezoar Stone, Credit: Wolfgang Sauber

The belief in the magical powers of the “bones” from a stag’s heart originates from a folk tale. The tale is that stags ate poisonous snakes by sniffing them out of holes and then after which they rushed to drink water. The “bones” in their heart were believed to be what protected the stags from being poisoned. The “bones” were actually caused by the degeneration of arteries into flat, oblong bone like objects. Powdering and consuming this “bone” was seen as a preventative measure to protect against the effects of poisoning (Jackson, 97).

Unicorn horn, bezoars and “bones” from a stag’s heart, were the key ingredients to the “Banisters Powder” in St. John’s recipe book. Because of the longstanding beliefs about these ingredients and their associations with poisoning detection, prevention and cures, this recipe was perhaps intended to cure or prevent poisoning. One can imagine the remedy would have been thought to be fool-proof against poison because it combined the powers of each of these ingredients. Although there was a movement away from magical remedies and cure-alls among physicians in the Early Modern period, belief in the curing power of magical objects was still present in the lives of home practitioners such as Johanna St. John. What we would consider scientifically impossible, they were only beginning to discover.

A strong belief in unexplainable phenomenon was common practice and popular beliefs are difficult to dispel, especially when they hold significant symbolic value. Just the other day the North Korean state media associated the discovery of a Unicorn Lair with their new young leader. It is hoped this association would strengthen the nation’s confidence in their young leader because of the symbolic meaning of the Unicorn and its ties to the state’s history. This example illustrates that a belief in the symbolic power of an object, like a Unicorn or its horn, bezoars, or “bones” from a stag’s heart can transcend both time and logic, persisting even when its truth is questionable.

Works Cited:

Auble, Cassandra. “The Cultural Significance of Precious Stones in Early Modern England.” Dissertations, Thesis, & Student Research, Department of History, University of Nebraska Paper 39 (2011).

Brockbank, William. “Sovereign Remedies: A Critical Depreciation of the 17th-Century London Pharmacopoeia.” Medical History 8.01 (1964): 1-14.

Jackson, William A. “Antidotes” Trends in Pharmacological Sciences 23.2 (2002): 96-98.

Knight, Katherine. “A Precious Medicine: Tradition and Magic in Some Seventeenth-Century Household Remedies” Folklore 113.2 (2002): 237-247.