How to handle when PCs taste a potion that is actually poison?

Question

I will soon be DM for the first time. As preparation, I have been reading the DMG and I found this rule on identifying a magic item page 136:

Potions are an exception; a little taste is enough to tell the taster what the potion does.

I have never seen this rule used in previous games as a player. We would always identify them like magic items: it takes a short rest or an identify spell.

I find the rule risky and wouldn't apply it as a player. If what the player assumes to be a potion is actually contact poison, he would automatically suffer the effects, right? Sounds like a stupid idea to me to taste some strange liquid I don't know.

How should I handle this as a DM if my players wish to taste what they assume to be a potion but is actually poison? Should I tell them that it smells "bad" and doesn't seem "healthy" to taste?

Answer 1

At your discretion a partial dose of poison may have (reduced) effects.

The DMG (pages 257-258) distinguishes between different kinds of poisons and how they take effect, by contact, inhaled, by injury or Ingested (DMG, p. 257):

Ingested. A creature must swallow an entire dose of ingested poison to suffer its effects. You might decide that a partial dose has a reduced effect, such as allowing advantage on the saving throw or dealing only half damage on a failed save.

Handle it at your discretion. Maybe you want to use the Variant rule on the same page (DMG, p. 136) that makes identification generally more difficult and adjust it by making it explicit that tasting potions is dangerous or bears no effect at all.

The narration of poisons are mostly at your discretion as well, you define whether they are tasteless, smell-less, indistinguishable (for that matter you also narrate the smell and taste of magic potions and you may indulge in that healing potions taste foul or like soap), etc. How identifying potions should work gives narrative techniques.

Contact poison only works on exposed skin by RAW, but as a DM you are free to change that (you should inform your players when you do that and before it has negative consequences for them) your character's lips and mouth technically are all mucous membranes and not skin. But I'm not arguing that point, if you think it is skin, then contact poison affects you while tasting. These mucous membranes of humans are even thinner than skin and in that way, realistically speaking, may be affected by contact poison (DMG, p. 257):

Contact. A creature that touches contact poison with exposed skin suffers its effects.

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The uncommon magic item (potion) Potion of Poison, (DMG, p. 188):

This concoction looks, smells, and tastes like a potion of healing or other beneficial potion. However, it is actually poison masked by illusion magic. An identify spell reveals its true nature.

tastes like the mimicked potion by illusion magic, that is it tastes like whatever potion it is masked as (which you can narrate as you like). Which is contrary to its true nature - revealed by an identify spell. So the actual taste is not that of the mimicked potion (which you can narrate as you like).

The tasting of a Potion of Poison replicates the look and smells with illusion magic. It does not replicate the healing effect or other benevolent potion effects.

Answer 2

A Potion of Poison tastes/looks/smells exactly like a Potion of Healing.

If you're talking about the Potion of Poison item:

This concoction looks, smells, and tastes like a Potion of Healing or other beneficial potion.

PCs that taste it will think it's a harmless Potion of Healing, and get a nasty surprise when the situation is dire.

Answer 3

It's a trap!

What you're describing is technically a trap (except in the case of the potion of poison, which would need to be fully drunk in order to have any affect), and you should treat it like one as a DM. You need to decide as the DM whether they detect the trap and whether they trigger its effects. If they trigger it in a cautious way, you may consider reducing the DC of the saving throw.

I should clarify, it doesn't have the intent of being a trap, what I'm saying is that you can treat it like a trap in this situation. I've come across this type of things a number of times as a DM, the players want to do something that is stupid (my players think it's funny to do stupid things, and they're right) and I essentially improvise a trap situation for them and attach an appropriate DC for them triggering it based on what exactly they are choosing to do.

Answer 4

Tasting a potion offers no insight into what it is. Potions, even of the same type, may have various tastes depending on various factors: who made it, how long has it been since it was made, how was it made, and so on. An example is that an elf making a potion wouldn't make it exactly the same as a human or dwarf or another race. Just like food, it can have personal things added to that creature's liking or to keep others away.