How Do Poisons Work in D&D 5e?
A poison reaches its target by contact, ingestion, inhalation or injury, and the target makes a Constitution saving throw against the poison's DC or suffers its effect. Poison is the quiet rule. One vial, one Constitution save, and a fight ends before Initiative, or a hero sleeps through it. Here is everything the SRD says about poison, quoted, with the odds worked out.
What Poisoned does
The condition itself is short:
Ability Checks and Attacks Affected. You have Disadvantage on attack rolls and ability checks.
Saves are untouched. A Fighter who hits a Goblin Warrior 55% of the time hits it 30.25% Poisoned (see Advantage and Disadvantage). Most of the nasty poisons add a second condition on top, such as Paralyzed or Unconscious, that lasts "while Poisoned in this way". End the Poisoned condition and the rider goes with it.
The four ways in
The SRD sorts every poison by how it reaches you:
Contact. Contact poison can be smeared on an object and remains potent until it is touched or washed off.
Ingested. A creature must swallow an entire dose of ingested poison to suffer its effects.
A partial dose is the GM's call; the SRD suggests "allowing Advantage on the saving throw or dealing only half as much damage on a failed save."
Inhaled. Poisonous powders and gases take effect when inhaled. Blowing the powder or releasing the gas subjects creatures in a 5-foot Cube to its effect.
Holding one's breath is ineffective against inhaled poisons, as they affect nasal membranes, tear ducts, and other parts of the body.
Injury. Injury poison can be applied as a Bonus Action to a weapon, a piece of ammunition, or similar object. The poison remains potent until delivered through a wound or washed off.
Only Piercing or Slashing damage delivers it. A poisoned mace does nothing.
All fourteen, with the odds
Every sample poison calls for a Constitution save. Odds to pass, plain and with Advantage (a Dwarf, an Antitoxin, Protection from Poison):
| Poison (type, price) | DC | Con +0 | Con +2 | Con +5 |
|---|---|---|---|---|
| Assassin's Blood (ingested, 150 GP) | 10 | 55 / 79.75% | 65 / 87.75% | 80 / 96% |
| Serpent Venom (injury, 200 GP) | 11 | 50 / 75% | 60 / 84% | 75 / 93.75% |
| Truth Serum (ingested, 150 GP) | 11 | 50 / 75% | 60 / 84% | 75 / 93.75% |
| Burnt Othur Fumes (inhaled, 500 GP) | 13 | 40 / 64% | 50 / 75% | 65 / 87.75% |
| Crawler Mucus (contact, 200 GP) | 13 | 40 / 64% | 50 / 75% | 65 / 87.75% |
| Oil of Taggit (contact, 400 GP) | 13 | 40 / 64% | 50 / 75% | 65 / 87.75% |
| Spider's Sting (injury, 200 GP) | 13 | 40 / 64% | 50 / 75% | 65 / 87.75% |
| Wyvern Poison (injury, 1,200 GP) | 14 | 35 / 57.75% | 45 / 69.75% | 60 / 84% |
| Essence of Ether (inhaled, 300 GP) | 15 | 30 / 51% | 40 / 64% | 55 / 79.75% |
| Malice (inhaled, 250 GP) | 15 | 30 / 51% | 40 / 64% | 55 / 79.75% |
| Torpor (ingested, 600 GP) | 15 | 30 / 51% | 40 / 64% | 55 / 79.75% |
| Pale Tincture (ingested, 250 GP) | 16 | 25 / 43.75% | 35 / 57.75% | 50 / 75% |
| Midnight Tears (ingested, 1,500 GP) | 17 | 20 / 36% | 30 / 51% | 45 / 69.75% |
| Purple Worm Poison (injury, 2,000 GP) | 21 | 0 / 0% | 10 / 19% | 25 / 43.75% |
A natural 20 is not an automatic success on a save, so Purple Worm Poison beats a Con +0 hero every time.
The ones that end fights
Crawler Mucus paralyzes: "The creature also has the Paralyzed condition while Poisoned in this way. The creature repeats the save at the end of each of its turns". A Paralyzed creature fails Strength and Dexterity saves and every hit from 5 feet is a Critical Hit. A Con +0 guard fails 60% of the time and stays down 2.5 turns on average; 13% are still frozen after three turns.
Spider's Sting knocks out only on a bad miss: "If the creature fails the save by 5 or more, the creature also has the Unconscious condition". At DC 13 that means a total of 8 or less: 35% at Con +0, 25% at +2, 10% at +5.
Essence of Ether and Oil of Taggit both put a creature to sleep, for 8 and 24 hours. Ether's sleeper wakes "if another creature takes an action to shake it awake"; Taggit's wakes only "if it takes damage".
Burnt Othur Fumes keeps biting: after a failed save the creature repeats it every turn, 1d6 per failure, until "three successful saves". From a failed first save, expect 26 damage at Con +0, 21 at +2, 16 at +5.
Pale Tincture is the slow one. The save repeats every 24 hours, "the damage the poison deals can't be healed by any means while the creature remains Poisoned", and it ends only "after seven successful saves". A Con +2 victim stays Poisoned about 20 days and takes about 49 damage on average; at Con +0, 28 days and 77.
Midnight Tears waits: "suffers no effect until the stroke of midnight." Any cure for Poisoned before then neutralizes it, so the counter is to suspect it.
A poisoned blade, by the numbers
Wyvern Poison deals 7d6 (24.5 average), half on a save. From full Hit Points, one dose drops a level 3 Wizard (20 HP, Con +2) 47.5% of the time, a level 5 Rogue (33 HP, Con +1) 2.3%, a level 5 Fighter (44 HP, save +5) never. Advantage cuts the Wizard to 26.1%; Resistance to Poison cuts it to 0.
Purple Worm Poison, 10d6 at DC 21, drops the same Wizard 91.9%, the Rogue 64.2%, the Fighter 4.4%.
The cheap option is Basic Poison (100 GP) from the gear list:
As a Bonus Action, you can use a vial of Basic Poison to coat one weapon or up to three pieces of ammunition. A creature that takes Piercing or Slashing damage from the poisoned weapon or ammunition takes an extra 1d4 Poison damage.
It lasts "1 minute or until its damage is dealt", so one hit.
Rogues and the Poisoner's Kit
A level 5 Rogue's Cunning Strike trades 1d6 of Sneak Attack for poison:
On a failed save, the target has the Poisoned condition for 1 minute. At the end of each of its turns, the Poisoned target repeats the save, ending the effect on itself on a success.
To use this effect, you must have a Poisoner's Kit on your person.
The DC is 8 + Dexterity modifier + Proficiency Bonus: 15 for Dex +4 at level 5. A Goblin Warrior (Con +0) fails 70% and stays Poisoned about 3.3 turns; an Ogre (Con +3) fails 55%, about 2.2 turns.
The kit (50 GP) also lets you "Detect a poisoned object (DC 10)" and craft Basic Poison.
Harvesting from a dead monster
The effort takes 1d6 minutes, after which the character makes a DC 20 Intelligence (Nature) check using a Poisoner's Kit.
If the character fails the check by 5 or more, the character is subjected to the creature's poison.
At Nature +5 that is 30% to get a dose and 50% to poison yourself. Proficiency with the kit as well as Nature gives Advantage (see Tools and Tool Proficiency): 51% and 25%.
Cures and protection
- Antitoxin (50 GP): "As a Bonus Action, you can drink a vial of Antitoxin to gain Advantage on saving throws to avoid or end the Poisoned condition for 1 hour." Drink it before the feast, not after.
- Lesser Restoration (level 2, Bonus Action): ends "one condition on it: Blinded, Deafened, Paralyzed, or Poisoned."
- Protection from Poison (level 2, Action, 1 hour): ends Poisoned, then gives "Advantage on saving throws to avoid or end the Poisoned condition, and it has Resistance to Poison damage."
- Lay on Hands: a Paladin can "expend 5 Hit Points from the pool of healing power to remove the Poisoned condition".
- Dwarven Resilience: "Resistance to Poison damage. You also have Advantage on saving throws you make to avoid or end the Poisoned condition."
- Monk, level 10 Self-Restoration: removes Charmed, Frightened or Poisoned from yourself "at the end of each of your turns".
- Brewer's Supplies: "Detect poisoned drink (DC 15)", and craft Antitoxin.
At the table
- Poisoned is Disadvantage on attacks and checks, nothing else. The rider is the danger.
- Read the DC first: 10 and 11 are coin flips, 15 and up beat most heroes.
- Injury poison needs Piercing or Slashing damage.
- Antitoxin before, Lesser Restoration after.
The Book of Dice covers the d20, Advantage and why a DC of 15 feels so much harder than 13 in Part III, The Rolling.
This work includes material from the System Reference Document 5.2.1 ("SRD 5.2.1") by Wizards of the Coast LLC, available at dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License.
