Detect poison -- what exactly is a poison?


Pathfinder First Edition General Discussion


It's obvious--anything that does poison damage. But is it obvious? Poison is a matter of dose.

For hazmat labeling anything with an oral LD50 lower than 300mg/kg is considered toxic aka poison. (50 mg/kg for highly toxic, 5 mg/kg for extremely toxic.)

Note that this includes many substances not intended to cause harm. I can think of multiple things I have around that would be considered toxic--despite being meant for human consumption! I'm not going to take the time to look up all the data but I'm pretty sure a couple would class as highly toxic.

Does detect poison ping on things like that--stuff that small exposures could easily kill but which aren't meant for killing? And what about the borderline cases--say, heroin?

(Or, for the ultimate case--the drug Wayfarin <b>is</b> rat poison.)


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I don't know. I don't recall seeing this question ever asked.

My best guess is that if anything can poison you in a single dose, such as poison in mug of beer, it'll register. A regular mug of beer shouldn't register. Many folks can have several drinks without side effects (maybe in the long term, but not today).


Things containing or otherwise capable of immediately delivering poison... poisonous snake, poisoned mug of beer, a hidden rogue with a vile of poison in their pocket or on their blade...

Things like a radioactive rock? Not so much.


I'm in agreement with OM - if being exposed to a substance in the proper way is enough to inflict mechanical penalties, it's a poison and will register with Detect Poison. A single bee sting will at worst be a little painful (ignoring allergies) but not be bad enough to do anything of note to a character, so shouldn't register. A giant bee sting injects enough stuff to be dangerous and would register. A full swarm of normal bees should register as well. This of course leads to the interesting case of creatures immune to poison casting the spell: does it register anything for them or not?
And to confuse things further with dosages: assuming a single pill of some medicine doesn't register, does an entire bottle (where consuming all of them could kill you)?


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Don't try to interject real world science into a game.

IF the stats item. creature, etc indicate something is poison then it is. If it doesn't then it's not. And there are probably corner cases, and a GM should adjudicate.

If the question is ultimately about "well this substance is dangerous for one particular character/race but is completely harmless to others" I tend to not have spells like detect poison work.

For instance, let's say someone is poisoned by water. Detect poison spell will not react.


My group has found the detect poison spell to be largely ineffective since our DM keeps having it register things that are only poisonous in very large doses as poison… such as mead… we were unable to tell the difference between a good poisoned mug of mead and an unpoisoned mug once because of this…

So I agree with the above sentiments… don’t inject real world science into how this spell works… it detects thing’s immediately poisonous, not things that are “potentially poisonous if you consume enough”… don’t make your players incapable of detecting poison in their mead…


Magic is often more about the intent. Is this substance here to poison someone? Then it's poison.


Chell Raighn wrote:

My group has found the detect poison spell to be largely ineffective since our DM keeps having it register things that are only poisonous in very large doses as poison… such as mead… we were unable to tell the difference between a good poisoned mug of mead and an unpoisoned mug once because of this…

So I agree with the above sentiments… don’t inject real world science into how this spell works… it detects thing’s immediately poisonous, not things that are “potentially poisonous if you consume enough”… don’t make your players incapable of detecting poison in their mead…

Yeah, I would be upset at such a DM because it seems like a highly adversarial relationship. If they're going to stop detect poison from working by making everything register as poisonous then no one would bother to use the spell. And trying to detect if your food/drink is poisoned seems like one of the primary use cases for the spell.

Now if the GM wanted to make it less easy, they could say that there needs to be some of check of your magical power vs the level(?) of the poison.

Edit: Reading the PF2 description of the spell your GM isn't necessarily wrong. It does explicitly say alcohol in a poison, and your mug of ale does contain alcohol.

But when heightened to a level 2 spell it should tell you what kind of poisons, and so you would know if it's just alcohol or something else.

Still...I really don't like that PF2 detect poison was written that way. It makes the spell fairly useless for it's classic purpose until you can cast 2nd level spells.

Edit 2: Just realize this was for PF1, so actually showing your GM the PF2 version of detect poison that explicitly allows for alcohol to mask other poisons might make the point. Alcohol in normal quantities isn't poisonous by most people's definition of poisonous.


For me poison detects anything that is a poison according to the list in Pathfinder poisons, if present in sufficient quantities to ruin the day of the smallest weight person in the party.

I will adjust on the fly if it can be used to detec CO concentrations in a mine shaft.


All PF2 suggests is that the original cantrip was maybe a little too good. In PF1 alcohol is never declared a poison.

But I now wonder how the PF2 change effects culture. Do royals and those in regular danger of being poisoned abstain from alcohol altogether. It seems like such a change in a suitably magical world would just evolve into alcohol being seen as nothing more than dirty commoner water.


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Melkiador wrote:

All PF2 suggests is that the original cantrip was maybe a little too good. In PF1 alcohol is never declared a poison.

But I now wonder how the PF2 change effects culture. Do royals and those in regular danger of being poisoned abstain from alcohol altogether. It seems like such a change in a suitably magical world would just evolve into alcohol being seen as nothing more than dirty commoner water.

Well, that or you have someone that can cast the level 2 version of the spell on retainer. If you're a noble or monarch, you can afford it.


Claxon wrote:
Now if the GM wanted to make it less easy, they could say that there needs to be some of check of your magical power vs the level(?) of the poison.

He did that too… though he had us roll craft (Alchemy) since thats the skill used to make poisons… which of course none of our casters with detect poison had any ranks in…


Claxon wrote:
Melkiador wrote:

All PF2 suggests is that the original cantrip was maybe a little too good. In PF1 alcohol is never declared a poison.

But I now wonder how the PF2 change effects culture. Do royals and those in regular danger of being poisoned abstain from alcohol altogether. It seems like such a change in a suitably magical world would just evolve into alcohol being seen as nothing more than dirty commoner water.

Well, that or you have someone that can cast the level 2 version of the spell on retainer. If you're a noble or monarch, you can afford it.

Looking at it more, the problem is more system wide. It's not even a cantrip anymore. You would need multiple spellcasters now to cast it enough to check every drink, unless everyone rarely drinks to begin with.

Although I guess "problem" is just relative to what you are trying to achieve. If you want to kill lots of notable people, then you're in luck.

Edit: Just noticed that the spell "enhance victuals" now makes all wine non-alcoholic.


Chell Raighn wrote:
Claxon wrote:
Now if the GM wanted to make it less easy, they could say that there needs to be some of check of your magical power vs the level(?) of the poison.
He did that too… though he had us roll craft (Alchemy) since thats the skill used to make poisons… which of course none of our casters with detect poison had any ranks in…

That makes no sense.

Your using magic, to determine if something is poison. Not any of your skill. This would greatly upset me as well.

It should have been something like a caster level check vs the DC of the poison.

Your GM sounds like either someone very inexperienced with Pathfinder or like an adversarial jerk kind of GM.


Melkiador wrote:
Claxon wrote:
Melkiador wrote:

All PF2 suggests is that the original cantrip was maybe a little too good. In PF1 alcohol is never declared a poison.

But I now wonder how the PF2 change effects culture. Do royals and those in regular danger of being poisoned abstain from alcohol altogether. It seems like such a change in a suitably magical world would just evolve into alcohol being seen as nothing more than dirty commoner water.

Well, that or you have someone that can cast the level 2 version of the spell on retainer. If you're a noble or monarch, you can afford it.

Looking at it more, the problem is more system wide. It's not even a cantrip anymore. You would need multiple spellcasters now to cast it enough to check every drink, unless everyone rarely drinks to begin with.

Although I guess "problem" is just relative to what you are trying to achieve. If you want to kill lots of notable people, then you're in luck.

Edit: Just noticed that the spell "enhance victuals" now makes all wine non-alcoholic.

You're right. You can only check specific items, because you certainly don't have enough casting per day.

So nobles will continue the tradition of having a taste tester.

Liberty's Edge

Chell Raighn wrote:
Claxon wrote:
Now if the GM wanted to make it less easy, they could say that there needs to be some of check of your magical power vs the level(?) of the poison.
He did that too… though he had us roll craft (Alchemy) since thats the skill used to make poisons… which of course none of our casters with detect poison had any ranks in…
Detect poison wrote:
You can determine the exact type of poison with a DC 20 Wisdom check. A character with the Craft (alchemy) skill may try a DC 20 Craft (alchemy) check if the Wisdom check fails, or may try the Craft (alchemy) check prior to the Wisdom check.

The exact type of poison is a bit more than knowing if something is poisonous for you.

Almost any food is poisonous. Even vitamins, which are indispensable to life, are toxic if the quantity is excessive.
It would have been more honest to remove the spell if he was bothered that much by it.


you're mixing Real Life technical details with Game Rules. Yeah, it's gonna get silly fast.

Game wise Poisons are Afflictions, all stuff we assume PC's don't want. What fun! Mostly poison effects are defined as once per round as the game is combat centric and nobody has time to wait days or weeks. Secondly the list is arranged by price. Hmmm, kinda telling you something. The fort save mechanic is also simplistic aimed at getting it over simply. Lastly dosages are unitized to keep the price levels in game balance (so you can stab then lick the weapon safely). It is very much about simplistic mechanics and price based on effect.

Detect Poison is going to work on stuff on that chart or highly similar items cooked up by your GM, and poisonous creatures. I don't think it'll detect an excess of vitamins, fiber (unless it has a defined stat block like a poison or RAW calls it a poison), or chocolate (aka Death by Chocolate).
Detect Poison isn't going to work on a vial of acid (except hydrofluoric which made the list), alchemist's fire, lye/draino, and pesh/nopalitos(purple pesh did make the list).
Game wise as soon as you say, "that's kryptonite!" it doesn't have any in game mechanical effect unless defined by your Home GM.
Allfood:T2{Rgr} becomes quite funny in this context.


At least one of the Tales line states that alcohol would ping Detect Poison (one of the Gantier brothers stories).

Do with this information what you will.


Carrauntoohil wrote:

At least one of the Tales line states that alcohol would ping Detect Poison (one of the Gantier brothers stories).

Do with this information what you will.

We already covered that in 2E, alcohol is considered a poison.

And while I disagree with that, it is written into the 2E version of detect poison.

In PF1, I'm not familiar with the exact story you're referring to and if it is even a PF1 story but I would prefer rulings like that not be made because it means you might as well not even bother with the spell.


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2E treats alcohol as poison? That definitely does away the point of the spell. The spell is supposed to determine whether someone put poison in your drink, not whether the drink itself will get you intoxicated. I guess we have to bring back the food tasters. Magic can't figure this out. ;p


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I don't see how this is complicated - Detect Poison pings on everything that is designated as "poison", by use of that game term. If the word "poison" doesn't appear in the description (or the description of anything referenced), it's not poison.


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OmniMage wrote:
2E treats alcohol as poison? That definitely does away the point of the spell. The spell is supposed to determine whether someone put poison in your drink, not whether the drink itself will get you intoxicated. I guess we have to bring back the food tasters. Magic can't figure this out. ;p

Intoxication comes from poisoning yourself with alcohol. Whichever way you spin that, medically, alcohol is poisonous and potentially deadly if go too far with it.

This makes for the spell working in a far more interesting way - it pings my wine, does it have death worm venom inside, or is it just going to really hurt me if I drink six bottles?

Liberty's Edge

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OmniMage wrote:
2E treats alcohol as poison? That definitely does away the point of the spell. The spell is supposed to determine whether someone put poison in your drink, not whether the drink itself will get you intoxicated. I guess we have to bring back the food tasters. Magic can't figure this out. ;p

That was done in 1st Ed AD&D, at least by some GM. Sow poison protected you from becoming drunk as long as it lasted, but you needed to use Neutralize poison to remove the alcohol or you ended up hungover.


Claxon wrote:
In PF1, I'm not familiar with the exact story you're referring to and if it is even a PF1 story but I would prefer rulings like that not be made because it means you might as well not even bother with the spell.

Like I said, do with it what you will. I'm not a cop [shrug]


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Derklord wrote:
I don't see how this is complicated - Detect Poison pings on everything that is designated as "poison", by use of that game term. If the word "poison" doesn't appear in the description (or the description of anything referenced), it's not poison.

This is an entirely justifiable reasoning.


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I, for one, do not mind introducing science into fantasy as long as it isn't too complicated to use. After all, one of the Paizo developers (I think it was James Jacobs) said in an interview a few years ago that Golarion's planetary nature (including size, shape, and gravity) is based on science, because that was easiest to work with.

Here's my take on how Detect Poison should work (some parts of this do NOT match with Rules As Written):

    [•]Detect Poison pings more strongly with more potent poison, assuming no measures to disguise the poison.
    [•]A quantity of poison that is too small to have an effect usually won't show. If you pass a Craft (Alchemy) or Heal check while using the spell, you can not only identify the poison, but also detect the poisonous nature of a does that is too small, but you will know that it is too small.
    [•]Something like alcoholic beverages that is normally consumed in non-poisonous doses that is present in sufficient quantity to be poisonous if all consumed detects as poisonous, but the diffuse nature of its toxicity is apparent. Think of it as being analogous to water with no other substances imparting color appearing faintly blue when present in great volume, but clear when in a small to medium container, unless you perform very sensitive detection of its optical properties.
    [•]If something that is poisonous only in excessive quantities is contaminated with something that is poisonous even in normally consumed doses, the latter dominates the detection; but with a successful Craft (Alchemy) or Heal, it is possible to detect both types of toxicity.
    [•]By default, when you learn this spell from a general source (such as a general deity), you use it to detect what is poisonous to you; however, with successful use of Craft (Alchemy) or Heal AND the appropriate creature identification knowledge skill, you can use it to detect what is poisonous to other kinds of creatures.
    [•]By default, when you learn this spell from a source that has particular conceptions of what is poisonous (such as from most Witch Patrons or some deity that normally only has one creature type as a worshipper), you use it to detect what is considered poisonous by that source, but with the proviso that said source can impart awareness of what is poisonous to creatures it considers important (essentially, a less refined version of the above); you can still use Craft (Alchemy) or Heal AND an appropriate creature identification knowledge skill as above, with a bonus if the creature type is one that is important to the source of this version of the spell. In this case, the aforementioned bonus is normally +2, but increases to +4 if you have at least 10 ranks in one of the relevant skills, and to +6 if you have at least 10 ranks in both of the relevant skills.
    [•]Obscure Poison works against Detect Poison, as advertised in the description of Obscure Poison.


If you believe the Game models reality then introducing some science is a good thing and the GM needs some expertise on the subject. I'd consider it increasing the accuracy and precision of the model.
However, d20 is far less accurate than standard old Newtonian physics so there's a basic systemic flaw. The game system is only designed to simulate something similar to a common experience and not break believeability.


^Basically, you need enough science for the cinematic aspect to work. (That said, I would like to know what some spells and supernatural effects would look like cinematically -- the descriptions are rather spotty in that department.)

Even so, I would like to see atomic elementals . . . .


like tha t-shirt sez, "Never believe atoms, they make up everything"


Related: Does 'Delay Poison' make you temporarily immune to the effects of alcohol?

Liberty's Edge

Matthew Downie wrote:
Related: Does 'Delay Poison' make you temporarily immune to the effects of alcohol?

RAW, no, because alcohol, for Pathfinder, is a drug and not a poison.

In actual play, it depends on your GM's opinion on how drugs and poisons work in the game. For me most if not all drugs are poisons, so "Delay Poison" would make someone temporarily immune to the effects of alcohol.


Diego Rossi wrote:
Matthew Downie wrote:
Related: Does 'Delay Poison' make you temporarily immune to the effects of alcohol?

RAW, no, because alcohol, for Pathfinder, is a drug and not a poison.

In actual play, it depends on your GM's opinion on how drugs and poisons work in the game. For me most if not all drugs are poisons, so "Delay Poison" would make someone temporarily immune to the effects of alcohol.

Yeah, I would class all recreational drugs as poisons, just not normally consumed in lethal amounts. I would say anything that blocks poison would block all recreational drugs, also, as well as any non-recreational things (if you're in a more modern world to have such things) which have detrimental effects (say, anesthesia) would likewise be blocked.

I like the idea above of it pinging if a lethal quantity is present and a check to detect lesser quantities.


PC: I rolled a 36 with Detect Poison!
GM: congrats on discovering that table salt could be a poison, as well as the most of the spices in the sauce, the pewter chalice with the wine, the table varnish, the ceramic plate (glaze), and the air from tobacco smoke. There's something about the asparagus on your plate and rhubarb tart dessert but do you have the technologist feat as it may just be part of their charm.


Poisons are so expensive, and often ineffective, that they are very seldom used... so the spell is of very limited importance, regardless of what it can and cannot actually detect. Finding a hidden Rogue with a poisoned blade is a corner case, but that same Rogue probably could have been found with Detect Magic, as well. Detect Poison might alert you to the giant spider lurking in the darkness... but you're in a freaking cave covered in spiderwebs, you shouldn't need a stupid spell to tell you there are spiders. Lol.

Liberty's Edge

VoodistMonk wrote:
Poisons are so expensive, and often ineffective, that they are very seldom used... so the spell is of very limited importance, regardless of what it can and cannot actually detect. Finding a hidden Rogue with a poisoned blade is a corner case, but that same Rogue probably could have been found with Detect Magic, as well. Detect Poison might alert you to the giant spider lurking in the darkness... but you're in a freaking cave covered in spiderwebs, you shouldn't need a stupid spell to tell you there are spiders. Lol.

True enough. A spell that would be very important in RL is relatively useless in play.

Part of the problem are the mechanics of poisons. They are very fast affecting to have an impact in play, but that makes them less useful.


This is interesting: I looked up detect poison and it lacked the comment in detect magic about being able to ignore sources that you already know about. And then I realised that detect magic does not have that bit either - so now I am wondering where I got it from!

Liberty's Edge

glass wrote:
This is interesting: I looked up detect poison and it lacked the comment in detect magic about being able to ignore sources that you already know about. And then I realised that detect magic does not have that bit either - so now I am wondering where I got it from!

Probably from:

"3rd Round: The strength and location of each aura."
It seems to suggest that you can focus on specific auras and exclude others, but the next pharagraph clarifies that it is the opposite, strong magical auras can hide weaker ones:
"Magical areas, multiple types of magic, or strong local magical emanations may distort or conceal weaker auras."

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