August 3, 2010 by

Medieval Poisons

Categories: Research, Tags: , , , , , , , , , , , , ,

King Henry I died in Normandy in 1135 of food poisoning “according to legend from eating a ‘surfeit of Lampreys’ (an eel type fish).”

In the new mini-series on Starz “Pillars of the Earth” based on the book by Ken Follett, he was deliberately poisoned by King Stephen (who succeeded him) or someone working for him.  For those watching the show, in point of fact, King Henry did not die within moments of the birth of Maud’s son, Henry (born 5 March 1133), who ultimately succeeded Stephen as King of England, but two years later.

King Henry died of food poisoning despite the high likelihood of having some kind of ‘food taster’.  Admittedly, such a person could be circumvented by a slow-acting poison.  In addition, in regular food poisoning, the effects are not felt for up to 24 to 48 hours, although 4-6 is also common.  Either way, a taster would not have been an effective stop to poisoning.

“The heavy burden of preventing poisoning appears was spread amongst a veritable platoon of servants, from the head cook to the lowliest server, each with the responsibility for specific and often repeated steps for ensuring that their liege lord did not succumb to a poisoning attempt. In The Art of Cookery in the Middle Ages, Scully describes a lengthy process for ensuring the master’s food was safe…

“Everything that was intended for the prince’s mouth became subject normally to two general sorts of tests, called assays: on the one hand, a test by means of a unicorn horn[crazy as it sounds], and on the other, a test by what vulgarly we might today call guinea-pig experimentation. This second sort of test needs no long explanation: it derived from the principle that one should oneself be willing to stand the salubrity of what one offers to others while making the claim that it is perfectly harmless….Clearly the test assumed that any poison effective enough to do in the prince — merely harming him could very readily prove in short order to be fatal to the poisoner instead! — would become manifest quickly and plainly enough to spare the prince the danger of ingesting it.”

The most common poisonous herbs in the Middle Ages were belladonna, hemlock, monkshood/wolfsbane, and foxglove.

Belladonna (Deadly Nightshade):  “Its deadly character is due to the presence of an alkaloid, Atropine, 1/10 grain of which swallowed by a man has occasioned symptoms of poisoning. As every part of the plant is extremely poisonous, neither leaves, berries, nor root should be handled if there are any cuts or abrasions on the hands. The root is the most poisonous, the leaves and flowers less so, and the berries, except to children, least of all. It is said that an adult may eat two or three berries without injury, but dangerous symptoms appear if more are taken, and it is wiser not to attempt the experiment. Though so powerful in its action on the human body, the plant seems to affect some of the lower animals but little. Eight pounds of the herb are said to have been eaten by a horse without causing any injury, and an ass swallowed 1 lb. of the ripe berries without any bad results following. Rabbits, sheep, goats and swine eat the leaves with impunity, and birds often eat the seeds without any apparent effect, but cats and dogs are very susceptible to the poison.

Belladonna is supposed to have been the plant that poisoned the troops of Marcus Antonius during the Parthian wars. Plutarch gives a graphic account of the strange effects that followed its use.”

Hemlock:  “Poison Hemlock can grow to be about 6 to 10 ft. tall. It has leaves and white flowerheads resembling those of parsnips, carrots, and water hemlock. It has a fleshy, white taproot, a main stem with characteristic light red spots and a disagreeable smell. All plant parts are poisonous. However, the seeds contain the highest concentration of poison. The conium alkaloids are volatile and can even cause toxic reactions when inhaled.”

Monkshood/Wolfsbane (Aconite):  “All the species contain an active poison Aconitine, one of the most formidable poisons which have yet been discovered: it exists in all parts of the plant, but especially in the root. The smallest portion of either root or leaves, when first put into the mouth, occasions burning and tingling, and a sense of numbness immediately follows its continuance. One-fiftieth grain of Aconitine will kill a sparrow in a few seconds; one-tenth grain a rabbit in five minutes. It is more powerful than prussic acid and acts with tremendous rapidity. One hundredth grain will act locally, so as to produce a well-marked sensation in any part of the body for a whole day. So acrid is the poison, that the juice applied to a wounded finger affects the whole system, not only causing pains in the limbs, but a sense of suffocation and syncope.

Some species of Aconite were well known to the ancients as deadly poisons. It was said to be the invention of Hecate from the foam of Cerberus, and it was a species of Aconite that entered into the poison which the old men of the island of Ceos were condemned to drink when they became infirm and no longer of use to the State. Aconite is also supposed to have been the poison that formed the cup which Medea prepared for Theseus.”

Foxglove:  “In 1775 an English doctor named William Withering (1741-1799) began studying the foxglove plant. He learned that an effective medicine for treating heart ailments could be made from drying leaves picked just before the plant blossomed and crushing them into a powder. Withering also discovered that this medicine, digitalis—one of a number of substances called found in the plant—could be poisonous if the patient was given too much. Withering was aware that digitalis was effective only in certain forms of dropsy (edema), but apparently did not associate this with the cardiac actions of the drug. Withering published his findings about digitalis in 1785, but in spite of his warnings about proper dosage, many doctors prescribed the medicine in doses that were too large and for sicknesses it could not cure.

The active principles of digitalis were not known to researchers until the mid-1800s, when two French scientists, Homolle Ouevenne and Theodore Ouevenne, found the substance digitalin in the foxglove plant. In 1875 Oscar Schmiedeberg (1838-1921) identified the potent chemical digitoxin in the plant, and in 1930 the English chemist Sydney Smith obtained the medicine used today, digoxin, from the wooly foxglove plant, Digitalis lanata.

Today doctors know that if too much digitalis enters the circulatory system the patient may experience nausea, vomiting, trouble with vision (seeing too much yellow or green), and a very slow and irregular heartbeat. A larger amount of digitalis can result in convulsions (severe seizures) and death. Even grazing animals that eat too much of the foxglove plant can become poisoned by its glycosides.”

Read more: Digitalis – used, anesthetic, blood, body, produced, plant, Foxglove, The Pharmacy in the Garden, Witherings Studies

18 Responses to Medieval Poisons

  1. Pingback: Virtual Skeptics #118 – 2/4/2015 | The Virtual Skeptics

  2. Janie

    For Theodora:
    The mold which grows on the grain rye, ergot or ergotamine can cause hallucinations, paranoia and violence. That might work in your story.

  3. Theodora

    Hello! I am currently trying to write an interactive story that takes place in the Middle Ages. Is there any poison that could become manifest in a few hours or so that could make the victims lose their senses and attack others indiscriminately? Also, is there another one that could cause paranoia, headaches and dizziness?
    (Just felt like adding: It is hard to find information if I search using my native language sometimes I don’t find any at all.)

    Thank you :)

    • Sarah Post author

      I honestly don’t know about any in particular with those symptoms. If I come across any, I’ll let you know.

  4. Michael

    When it comes to the poison Belladonna, what do dogs, cats, and humans not have compared to the birds and other animals that can eat it without being harmed?

  5. Doug

    I just watched the movie Robin and Marian. At the end Marian poisons Robin Hood. I have been trying to figure what poison she used. His symptoms included lack of pain from his various serious wounds and loss of feeling in his legs. Any ideas?

    • Sarah Post author

      Poppy juice? It would have to be something that stops the pain and kills him, as well as something that she would have had access to in the Middle Ages. My herb book said that it in addition to easing pain and causing sleep, it can increase ‘paralytic disorders’ and cause death.

  6. Martha Ferris

    Thrilled to have found your site!
    With Foxglove, does it build up in the system? Looking for a 12th century medication that caused harm, was withdrawn and then, when it is re-introduced from a flask others used, the character dies but the others don’t. Conflict in story between a healer (who pours the last drink and is then charged with murder) and the actual murderer who set up the scenario. Perhaps my scenario is impossible – but when I read this article it seemed, just maybe . . . Thanks!

    • Sarah Post author

      I know that arsenic builds up in the system. Looking at some entries, I think you could do this for foxglove. It would have to be just the right amount, however, and it’s unlikely that the others drinking it wouldn’t at least become ill. Maybe the poisoned person would have been a known to over-indulge? So the others drank a little and he drank a lot?

  7. simon lloyd

    Hi Sarah,

    I wondered if you would be kind enough to pass on your expert thoughts in regards to effects of a specific medieval poison on the human body, just before death.

    I am performing in The Canterbury Tales and myself and another actor have to realistically react to being poisoned and want it to be as accurate as possible.

    Could you give us some pointers please?

    Many thanks,

    Simon Lloyd

    • Sarah Post author

      For deadly nightshade (belladonna): “A peculiar symptom in those poisoned by Belladonna is the complete loss of voice, together with frequent bending forward of the trunk and continual movements of the hands and fingers, the pupils of the eye becoming much dilated.”

      For aconite: “The respiration becomes slower owing to a paralytic action on the respiratory centre and, in warm-blooded animals, death is due to this action, the respiration being arrested before the action of the heart. Aconite further depresses the activity of all nerve-terminals, the sensory being affected before the motor. In small doses, it therefore tends to relieve pain, if this is present. The activity of the spinal cord is similarly depressed. The pupil is at first contracted, and afterwards dilated. The cerebrum is totally unaffected by aconite, consciousness and the intelligence remaining normal to the last.”

  8. Michelle Kleih

    A very useful post, thanks for this! Question: During this period, it was common for women to use belladonna cosmetically (hence the name). Do you happen to know what the dosage difference would have been between the cosmetic usage and poisoning? Also, I’m wondering what sort of immunity a woman might develop against it.

    • Sarah Post author

      Belladonna does mean ‘beautiful lady’ in Italian. “The common name belladonna originates from its historic use by women . . . Drops prepared from the belladonna plant were used to dilate women’s pupils, an effect considered attractive. Today it is known that the atropine in belladonna acts as an antimuscarinic, blocking receptors in the muscles of the eye that constrict pupil size. Belladonna is currently rarely used cosmetically, as it carries the adverse effects of causing minor visual distortions, inability to focus on near objects, and increased heart rate. Prolonged usage was reputed to cause blindness.”

      I cannot find any reference to developing immunity to it, rather, overuse resulted in adverse side effects (blindness, death).