What are the rules on using poisons

[Sir cryosin]

How much is in a vial?
How long does it last?
How many attack can the poison last?
Ect... Ect....

[Ninja_Prawn]

How much is in a vial?
How long does it last?
How many attack can the poison last?
Ect... Ect....

All of these questions are answered by page 153 of the PHB.

A vial is four fluid ounces (grumble); this is implied to be one 'dose'.

Basic poison dries up and becomes ineffective after one minute. The books don't say how long the others last, but it seems safe to rule that the one minute is typical for all injury, contact and inhalation poisons. Perhaps one would be more lenient with ingestion poisons. And I'd probably offer special ways (i.e. with a cost attached) of making poisons stay active for longer.

The duration of the poisoning is listed in the poison's description; most end on a successful save.

One dose of poison on a melee weapon applies to the first attack that hits, then it is spent. You could potentially do more damage by spreading it over three arrowheads, but you run the risk of missing with all three (whereas the assumption is you're not going to miss with ten rounds of melee attacks).

Remember: applying poison to a weapon is an action, but you can do it with Mage Hand and Arcane Tricksters can control their Mage Hand with a bonus action.

[Falcon X]

If you are the DM or can get approval from one, this is a wonderful homebrew for making, buying, selling, and using poisons, herbalism, and alchemy: https://www.reddit.com/r/dndnext/comments/3w1log/5e_herbalism_alchemy_v12_updates_fanmade/

[Sir cryosin]

Wasn't there a sage advice or a errata thar changes the rules?

[Ninja_Prawn]

Wasn't there a sage advice or a errata thar changes the rules?

Possibly, though a quick google doesn't reveal anything dramatic. Some bits of the DMG were re-worded in the errata, but I can't see anything that changes the core mechanics.

[RickAllison]

Wasn't there a sage advice or a errata thar changes the rules?

The errata made it so it only affected one hit per application on a melee weapon. Before, you could have someone's poisoned blade affecting every attack until it dried up. Now, it goes away after one application.

[Ninja_Prawn]

Before, you could have someone's poisoned blade affecting every attack until it dried up.

*reads original text closely* Hm. I suppose you could have. If you were a dishonourable scoundrel!

[Goober4473]

According to the PHB, DMG, sage advice, and erratas, basic poison kind of works differently from other poison:

Basic: Apply to a melee weapon or three pieces of ammunition. Dries up after 1 minute, or after it is delivered (once each for ammunition).

Injury poisons from the DMG: Apply to a melee weapon or one piece of ammunition (or trap, etc.). Dries up only when delivered or cleaned off.

[RickAllison]

*reads original text closely* Hm. I suppose you could have. If you were a dishonourable scoundrel!

My PC's (of the time) favored method of gagging a prisoner was shoving a severable flask of acid in his mouth so if he bit down, his mouth would fill with potent acid. I'm just RPing :smallbiggrin:


According to the PHB, DMG, sage advice, and erratas, basic poison kind of works differently from other poison:

Basic: Apply to a melee weapon or three pieces of ammunition. Dries up after 1 minute, or after it is delivered (once each for ammunition).

Injury poisons from the DMG: Apply to a melee weapon or one piece of ammunition (or trap, etc.). Dries up only when delivered or cleaned off.

I like it that way, since it seems the basic poison is supposed to be the low-risk, low-reward poison. Easily obtained and easily lost.

[Oramac]

The errata made it so it only affected one hit per application on a melee weapon. Before, you could have someone's poisoned blade affecting every attack until it dried up. Now, it goes away after one application.

That is really dumb. Guess it's time to homebrew a dagger with a poison vial built into the hilt.

[Ninja_Prawn]

That is really dumb. Guess it's time to homebrew a dagger with a poison vial built into the hilt.

That already exists - as a magic item (page 161 of the DMG).

[Oramac]

That already exists - as a magic item (page 161 of the DMG).

Nah. I'm talking about something that can be used to reapply poison more than once during combat, even if there's no rider effect. If I'm going to take the time and gold (poison is expensive!) to build around using poison, I damn well ought to be able to use it more than once per combat.

[RickAllison]

That is really dumb. Guess it's time to homebrew a dagger with a poison vial built into the hilt.

I actually do it with the scabbard, so I don't lose integrity of the weapon and it is poisoned every time I draw it. Combine that with a few different daggers and throwing weapons can become quite potent...

[Oramac]

I actually do it with the scabbard, so I don't lose integrity of the weapon and it is poisoned every time I draw it. Combine that with a few different daggers and throwing weapons can become quite potent...

Good idea. Now to homebrew a Blinkback Belt from Pathfinder into 5e.....

[Quintessence]

All of these questions are answered by page 153 of the PHB.

A vial is four fluid ounces (grumble); this is implied to be one 'dose'.

Basic poison dries up and becomes ineffective after one minute. The books don't say how long the others last, but it seems safe to rule that the one minute is typical for all injury, contact and inhalation poisons. Perhaps one would be more lenient with ingestion poisons. And I'd probably offer special ways (i.e. with a cost attached) of making poisons stay active for longer.

The duration of the poisoning is listed in the poison's description; most end on a successful save.

One dose of poison on a melee weapon applies to the first attack that hits, then it is spent. You could potentially do more damage by spreading it over three arrowheads, but you run the risk of missing with all three (whereas the assumption is you're not going to miss with ten rounds of melee attacks).

Remember: applying poison to a weapon is an action, but you can do it with Mage Hand and Arcane Tricksters can control their Mage Hand with a bonus action.

I remember a errata to those rules that changed it from 1 minute to the poison lasting on the blade or arrow until used.

[RickAllison]

Good idea. Now to homebrew a Blinkback Belt from Pathfinder into 5e.....

I always thought it was a fun thing to consider :smallsmile:. Got the idea from Assassin's Creed 2, where Leonardo specifically discusses how difficult it was to include the poison in the blade without causing it to break in combat. I like the idea of having specific notches near where the blade meets the crossguard that cut open the loaded container in the scabbard when the weapon is drawn, then trigger the next cartridge to load once it is in position.

[Oramac]

I always thought it was a fun thing to consider :smallsmile:. Got the idea from Assassin's Creed 2, where Leonardo specifically discusses how difficult it was to include the poison in the blade without causing it to break in combat. I like the idea of having specific notches near where the blade meets the crossguard that cut open the loaded container in the scabbard when the weapon is drawn, then trigger the next cartridge to load once it is in position.

That would be cool. The thing D&D has that Assassin's Creed doesn't is magic, though. I could easily see a magically reinforced dagger that could stand up to combat and still allow more than one poison dose per day (like the dumb Dagger of Venom in the DMG). Surely it would be very rare and/or very expensive, but it would be a lot of fun.

[RickAllison]

That would be cool. The thing D&D has that Assassin's Creed doesn't is magic, though. I could easily see a magically reinforced dagger that could stand up to combat and still allow more than one poison dose per day (like the dumb Dagger of Venom in the DMG). Surely it would be very rare and/or very expensive, but it would be a lot of fun.

I try and stay away from items that are magical so I can actually make them. Of course, I'm studying to be an engineer, so designing mundane ways to recreate or foil magical things sounds awesome to me :smallsmile:

[Goober4473]

That is really dumb. Guess it's time to homebrew a dagger with a poison vial built into the hilt.

One of my characters has a +1 dagger like this. On a hit, I can choose to inject poison (or acid), and it uses 1/10 of the vial per "dose." My DM ruled acid vials only do 1d6 not 2d6 damage with it, but I get 10 doses out of any poison vial.

It's turned out to be incredibly powerful, and I can now see why poisons are 1 hit per vial. Basic poison is kind of not worth it, but the rest are quite powerful.

[Kryx]

Poison was always lost in 1 attack in 3.X. It is much more balanced that way so I prefer it.

[Oramac]

One of my characters has a +1 dagger like this. On a hit, I can choose to inject poison (or acid), and it uses 1/10 of the vial per "dose." My DM ruled acid vials only do 1d6 not 2d6 damage with it, but I get 10 doses out of any poison vial.

It's turned out to be incredibly powerful, and I can now see why poisons are 1 hit per vial. Basic poison is kind of not worth it, but the rest are quite powerful.

I can see it being one hit per vial if it were cheaper, but even the basic poison is 150 gp per dose. That's really damn expensive. If it were 1/10th that cost, sure. But not at that price.

[EKruze]

I think it's entirely reasonable to allow it to work for the full minute. If you're hitting 60% of the time, a foe is failing its DC 10 Con save 40% of the time and you're striking twice per round you can expect the PHB basic poison to do 12 damage over the ten rounds until it dries at the cost of an action to apply it. It's hard to justify its use if it wears off after one hit at does 2.5 average damage on a failed save at the expense of 100gp and an action.

[Goober4473]

I can see it being one hit per vial if it were cheaper, but even the basic poison is 150 gp per dose. That's really damn expensive. If it were 1/10th that cost, sure. But not at that price.

Except that it's basically free extra damage since there's very little else to spend money on. I have plate armor, and thousands of gold to spend, so I just buy poison. If there's anything else to spend money on, like if you allow buying magic items, it gets less awesome, but as-is, there's nothing really to compare it to. It's either poison or like, land and cool art to hang in your house.


I think it's entirely reasonable to allow it to work for the full minute. If you're hitting 60% of the time, a foe is failing its DC 10 Con save 40% of the time and you're striking twice per round you can expect the PHB basic poison to do 12 damage over the ten rounds until it dries at the cost of an action to apply it. It's hard to justify its use if it wears off after one hit at does 2.5 average damage on a failed save at the expense of 100gp and an action.

For basic poison, I'd generally agree, but it's still bonus extra damage on top of whatever your class does. If you have money and no need to buy better armor, basic poison is better than coins in your pocket, but a poor choice if other poison is available.