How would a medieval doctor identify a poison that was administered through a cut? Is it strictly by symptoms? If the implement is produced, would that help in identifying the poison?

The story is fantasy, but I've tried to stick closely with historical and medical facts from medieval times--14th to 15th century. The doctor is a soldier with training in medicine. The government has been allowing medical experimentation and study to an extent, so he is experienced and learned for my purposes, but limited by lack of scientific and medical technology.

Also, implement is a dagger, and yes it can be provided. Poison is a combination of plant, venom, and minerals, so symptoms would be difficult to diagnose.

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    $\begingroup$ Hey Christye, welcome to WorldBuilding! Could you be a bit more specific about what tools and chemistry this doctor has? Also, are you looking for general diagnostic techniques or symptoms of a specific poison? This is an interesting question so I hope you can clarify what you're looking for. $\endgroup$ – Green May 10 '17 at 18:57
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    $\begingroup$ Do you want to know what an actual medieval would have done? Or what a modern could do with medieval tools? $\endgroup$ – Willk May 10 '17 at 19:02
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    $\begingroup$ You probably want to add a filter of the Poison on the wound is apparent or not. This would limit it to Symptoms. If the poison is apparent on the wound but not known, then the implement may be useful. $\endgroup$ – Enigma Maitreya May 10 '17 at 19:02
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    $\begingroup$ There are sort of two ways this question could be interpreted: "How could a doctor identify the effects of specific poison x?" (where you would have to tell us what poison x is), or "how could a doctor identify if someone with a cut has been poisoned?" $\endgroup$ – kingledion May 10 '17 at 19:03
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    $\begingroup$ This is not story based, the question is simply "Considering a medieval setting would a doctor be able to identify x-poison that was delivered in x-manner" $\endgroup$ – James May 10 '17 at 19:24

If this happened the first time and the patient is dead without any characteristic symptoms - random luck.

If various poisons are regularly inserted through cut - thanks to some detective work.

If the poison has very specific symptoms (let's say hair loss and bleeding from the nose), he might be able to identify the poison.

Also by talking to the patient. The patient tells them he was cut by some guy and then he started having symptoms - most doctors can put 1 and 1 together. Even today doctors have trouble identifying the poison and mostly do it by the patient telling them what happened.

Also please be aware that a doctor in those times wasn't an intellectual (not that they are today, but often in fiction) that could solve hard puzzles, but rather a barber, for example, that also did some doctoring.

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    $\begingroup$ Get your appendix taken out with your shave. $\endgroup$ – user2259716 May 11 '17 at 15:41
  • $\begingroup$ The good old days $\endgroup$ – Raditz_35 May 11 '17 at 15:44
  • $\begingroup$ That's why barbers poles are red and white, blood and bandages. $\endgroup$ – Sarriesfan Jul 7 '17 at 18:57

There are plenty of options available, but it would depend a lot on the training of the "doctor" whether they would recognize the clues.

Some plant based poisons would have a faint smell. Some would cause a certain reaction on the skin around the wound, it might cause dilation of the pupils, a rash across their skin, etc. If they knew how long the reaction took (a witness saw the person attacked and how quickly they fell sick) that would help narrow it down.

In general though you will need the character diagnosing to have some training with herbalism. A monk might have had some training in that area. You will have to do some studying yourself to find specific poisons and their effects.


Laboratory testing as we know it today, did not exist in medieval times. The doctor would have use his own senses, he could smell the poisoned blade or look for residue. Another option would be to apply the poison/ blade to an animal to observe the symptoms. Otherwise, it would be based on the poisoned person's symptoms. Also note that autopsies were not performed in the Middle Ages either.


Short answer, a Medieval doctor of our world be unlikely to be able to do what you're looking asking.

Medical experimentation and autopsies were not an accepted part of culture until much later than this historically in our world. However, that doesn't mean that you can't build a world where this is possible, there will just have to be specific changes in culture and science made.

In the late 1400s in Padua and Bologna, Italy, the sites of the world's first medical schools, Pope Sixtus the IV issued an edict permitting dissection of the human body by medical students. Before such edicts from religious leaders, it was considered a crime to dissect the human body and criminal prosecutions for "body snatching" by students of anatomy date back to the early 1300s.

By the 1500s, the autopsy was generally accepted by the Catholic Church, marking the way for an accepted systematic approach for the study of human pathology. While a number of "giants" around this time, such as Vesalius (1514-1564), Pare (1510-1590), Lancisi (1654- 1720), and Boerhaave (1668-1738) advanced the autopsy, it is Giovanni Bathista Morgagni (1682-1771) who has been considered the first great autopsist. SOURCE

If you're talking the 1400s (which is the 15th century) there just hadn't been enough experimentation in order to really do what you're talking about. You'd need hundreds of years of acceptance and schools to get to a place where someone might be able to accurately declare the cause of death.

And what you're talking about is actually forensics. And chemistry. By the 1600-1700s, we'd started to get a grasp on chemistry, a bit, but we were not at the level of forensics.

This practice was actually born later, in the Victorian Age, when the collective observations of hundreds of doctors and students through the ages, plus a start to understanding chemistry gave it a boost. It was nowhere near as good as it is today, but this was the start. See this article on how they first figured out arsenic poisoning in the 1800s. You'll notice that observational experimentation and the recording of those results, along with knowledge of chemistry was used.

So your proto-pathologist would have to be, gosh, 300-400 years more advanced than everyone else, if you are using the real world as a basis. Even if he's a genius, keep in mind that he cannot have seen everything, and pathologists, of this time and that relied on books published on the subject, the experimentation and observation of others.

The answer here is that you are going to need to change your world a bit. It has to have been a) acceptable for many years (perhaps hundreds) to cut into dead people as a method of learning b) there have to be books or sources of information from which to learn c) there has to be a base scientific knowledge of chemistry, even if it isn't fully understood.

In the Victorian era even, sharing information of this sort did not happen quickly, but you will notice a spate of landmark cases from about 1800-1900 as the science was born.

A person you might want to look at is: Alexandre Lacassagne from France. Don't look so much at the psyche work he did. There's a lot of bunk there, although he is better than his Italian counterpart, Cesare Lombroso, who was big into equating physical body types with a predisposition for criminality. Still, it would be interesting to have a protagonist who is right about forensics but attributes criminality to something crazy like phrenology or an imbalance of the humors.

You say that:

Poison is a combination of plant, venom, and minerals, so symptoms would be difficult to diagnose.

One of these can easily cloud the symptoms of the other, but if the combo is known--that can help. Some poisons have physical symptoms attached to them that could be easy to see--it's up to you as the author to attribute them--so the pupils normally dilate pretty quickly after death--but one of your poisons might prevent that for a few hours or it could be something like the rosy glow present in bodies that have died of carbon monoxide poisoning, or any number of purely physical tells, like body positioning as a result of muscle convulsions, that sort of thing. The quicker they get hold of the body, the more likely they can start to come to conclusions (except in the case of some poisonings, a symptom of which can be body preservation).

Your proto-forensics guy might understand that when a certain compound is present, it turns blue when mixed with urine/ammonia. He might not know why, but he could know that it's true.

The wound might be obvious or small, but an inspection of the body would reveal it. Then, he would perhaps dissect the area and test the tissue, looking for anything out of place. A great help would be the invention of the compound microscope or something very like it, although you might be able to get away with an efficient magnifier.

The Maesters of Game of Thrones are a pretty good guide to upping science patchily. They have a repository of knowledge, and "earn their chains" by studying certain sciences. In this way, RR Martian has been able to slip in things a little beyond the day as part of the world (which is different from ours) and you can do the same.


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