Revisiting Poison

Last updated: 171230… 210717

With perhaps the exception of level drain, little is feared more than poison, with a character’s destiny hanging on a single saving throw. Yet the odds of avoiding poison are low. 10% of all monsters in the MM are poisonous; in particular, many of the early monsters (spiders, snakes, centipedes). Appendix A suggests that 35% of all treasure is guarded by poison. While Appendix G suggests that only 7% of the traps include poison, that frequency in modules is much higher; there’s likely not a module written without the ubiquitous poison needle trap. Roughly 15% of all summoned monsters are poisonous.

Indeed, the DMG suggests limiting players’ use of poison, as character use is undesirable. Non-evil clerics and paladins can’t use poison at all (paladins won’t even adventure with a group that uses poison). Assassins can’t create poison until 9th level, and then only after months of study at a cost of ~60,000 gp (even then a single dose of poison takes a week to construct for another 200-1,200 gp).

Despite extensive notes on assassins’ use of poison, the DMG encourages sanctions for character use of poison (if not disallowed for characters entirely!). Thieves can set poison traps, but can’t wear any protective hand gear so failure setting the trap means poisoning themselves. Envenoming a weapon is “difficult” per the DMG, and the PHB tells you it’s not generally possible to envenom a weapon. Another recommendation is checking if the PCs nick themselves when handling poisoned weapons. Even then, poison on a blade wears off after only two blows. Character types other than assassin automatically grant a further +2 save to poison when striking with a poisoned weapon due to their inability to apply it effectively (and even assassins grant +1). Assassins using a poisoned weapon further risk their poison being noticed—a cumulative 10% per round. If any onlooker spots the poison, they will attack, call the Watch, or both! The DMG further recommends that characters discovered with poison be killed and their ashes scattered (causing permanent death, removing any hope of being raised from the dead)!

In this universe of limiting poison for players, monsters get relatively free reign. While real-world neurotoxins take 5-10 minutes, most monster poisons in AD&D are instantaneous all-or-nothing; the character either makes the saving throw or dies immediately (“within a minute or so”). In a combat scenario, that increases the odds that other characters will be attacked and poisoned in turn, as the poisonous attacks turn elsewhere.

A number of creatures can even shrug off the effects of poison. All swine, wereboars included, will be in this protected class. Similarly, very large creatures poisoned by very small ones are not likely to be affected. Even the poison of the deadly coral snake would not be likely to harm an apatosaurus. Giants would simply smash giant centipedes without fear of their poison—which would cause a swelling and rash, perhaps, at worst.


Once poisoned, a character has limited recourse. While holy water will “slow the onset of poison” (DMG Appendix), the specifics aren’t defined. The DSG Healing proficiency declares efficacy only when used “immediately” after poison, even though poisoned characters die “immediately.” WSG defines the efficacy of the Healing proficiency as “beginning in the same round that the poisoning occurs,” almost impossible within the constraints of the initiative system which doesn’t permit “within a round.” It’s improbable that the intent of those proficiencies was working only when the party is surprised, loses Initiative, or has declared they’re going to treat someone for poison who hasn’t been poisoned yet!

Character Classes

Monks aren’t immune to poison until 11th level. Barbarians have only a 10% chance of effecting a cure (50% + CON Score if the poison is known). The druid Slow Poison includes only a 5% chance / level to know a herbal antidote (and then only if the poison is made from a plant).

Even with a cleric, there’s not much a party can do. Normal healing doesn’t cure poison. Purify Food/Water will remove the poison from a substance, but not after the poison has affected a character. Slow Poison will take effect only if cast within 1 turn/cleric’s level after the character is poisoned, so the spell can be cast only once (twice if timing things to eke out every moment) before time runs out for the unfortunate character. The recipient of Slow Poison loses 1 hit point per turn (to a minimum of 1 hit point) for the duration of the spell (6 turns/level of the caster). However, unless the party is within a few hours of a 7th level cleric with Neutralize Poison (at the cost of 1,000 gp), Slow Poison won’t make any difference; Slow Poison will wear off and the PC will die.

Neutralize Poison is, as written, almost worthless. Neutralize Poison takes 7 segments to cast—hard to complete part way through a round. Characters will already have failed their saving throw and be dead. If a party cleric needs to pray for Neutralize Poison, it will take almost seven hours, far longer than any hope from Slow Poison. The cleric can always choose to attack the poisonous creature in melee and attempt to neutralize its poison in advance!

Magic Items

Magic items are more likely to poison than to cure. 3% of potions are poison. The Staff of the Serpent has a poisonous strike, and the Dagger of Venom will permit use of poison without observation. The Cloak of Poisonousness just kills characters. There are few magic items to aid a poisoned character. If applied in advance, Sweet Water will negate a Potion of Poison, but destroys other potions as well, negating any prophylactic use. The Periapt of Proof Against Poison only decreases the chances of being poisoned. The only magical cure available to PCs is Keoghtom’s Ointment, encountered .02% of the time.

Holy Water

The Appendix of the DMG indicates that holy water can slow the effects of poisons, with no further detail. The only defined effects of holy water are slowing the onset of lycanthropy or becoming undead for 1-4 turns. One extrapolation therefore would be that holy water delays the onset of poison by a similar duration. Dragon #081 suggests that holy water acts as Slow Poison with the duration as cast by a 1st-level cleric (6 turns/1 hour), where the first dose of holy water must be administered within 1 turn minus 2-5 segments of the time of poisoning to have the desired effect. Effects of multiple applications of holy water are cumulative with respect to duration; a double dose extends the effect for 2 consecutive hours (as long as the second dose is administered before the first one wears off).

Cleaning up the Timing

Death from poison takes effect immediately (defined as “a minute or so”) but clearly the precise timing matters. Time to use proficiencies, cast Neutralize Poison, drink holy water, or apply other remedies, and the party could be engaged in combat. Exactly how long does it take to die of poison?

Slow Poison, an only 2nd level spell, causes a supposedly dead character to have life restored if cast within a number of turns equal to the level of the cleric. The implication on “supposedly” is that poisoned characters aren’t actually dead, just close enough that the difference can’t be discerned. If the character is indeed not truly dead, Neutralize Poison should likely work within the same window (1 turn / caster level), although the two spells are not the same (Slow Poison is necromantic but Neutralize Poison is Alteration). Extending that logic further, spells affecting poison should take effect if used within 1 turn/caster level (magic items are defined as cast by a 12th level caster). Since holy water works within a turn, it follows that the proficiencies be defined in a similar manner. That timing is then consistent with the timing of zero hit points when poisoned, and death one turn later at -10. In the Expert Set, Neutralize Poison revives a victim if cast within 10 rounds of the poisoning, also aligning with poison taking the PC to 0 hp, followed by 10 rounds of -1 hp / round.

Yet the ability to cure poison with no negative effects is in and of itself inconsistent. Slow Poison slows the damage to 1 hit point / turn, but there’s no baseline of damage from “instant” poisons. Yet most purchased poisons do damage if survived.

Death Isn’t Instant?

Poisons are divided into monster poisons and those purchased (or concocted). Monster poisons are an all-or-nothing immediate affair. Yet the DMG lists purchased poisons with a variety of onset times, and damage and/or death depending on the save. Most of them cause damage instead of immediate death. Why do some poison potions do damage that can be healed, yet normal healing doesn’t help a character affected by an immediate poison? Poison causes physiological damage (the cause of death). When a character is poisoned why don’t hit points factor in? While healing can’t remove the poison, healing should be able to repair the damage caused.

Slow Poison’s effect implies that even immediate poison does physical damage that occurs over time, given that Slow Poison reduces that rate to 1 hit point/turn. Inferences from Slow Poison are that actual death from poison takes a while. What if we try to tease that apart? What if we consider the damage effects of poison?

If the 2nd level Slow Poison brings character back to life it would be disproportionately powerful. It’s clearly 2nd level not for balance, but because the spell is necessary with “immediate” poison. If death is defined as “in a round or so,” what happens during that time? Poison effects aren’t specified in the time just before death.

One way to address the conundrums of hit points and immediacy is to modify the poison mechanic to incorporate hit points. If the character fails their save, treat all poisons as ongoing damage, losing hit points until death. For those poisons that do a fixed amount of damage, that damage will accrue over time. For those poisons that cause immediate death, the PC will arrive there when they run out of hit points, collapsing at 0 hit points and dying at –10. Using hit points also resolves a separate question of what happens when a PC is poisoned twice—the rate doubles. Higher level characters appropriately survive longer when poisoned.

With the incorporation of hit points, death is delayed, yet the unaided result will be similar. An unaided PC will survive long enough for the party to react, yet still perish before the party can typically reach external aid. If Slow Poison is cast within a round or two, the PC’s hit point loss will only vary by a point or two. If the party has Neutralize Poison available (in whatever form) they’ll neutralize the poison, but as an alteration spell Neutralize Poison won’t heal the damage done. Neutralizing the poison prevents further damage, but doesn’t heal the damage. Healing doesn’t remove poison, but can heal the damage. 1 hit point / round is fast enough to carry real risk, but slow enough for the party to respond. This model also incorporates hit points, which provides another way to extend the PCs life while seeking recourse—healing.

The virulence of monster poisons varies, as suggested by bonuses (or penalties) to the saving throw. That can be represented by varying the amount of damage per round caused by poison. If the base amount of damage / round was 1, a saving throw bonus of +4 could reduce that to only 6 hit point/ turn, where a save penalty of -2 could increase damage to 12 hit points of damage / turn.

Normally PCs affected by poison are immediately incapacitated, yet using hit points to determine time of death doesn’t represent that effect. A solution would be using character Constitution: when the PC takes more poison damage than their Constitution, they’re incapacitated. Those so incapacitated would be disabled/unconscious for d3 turns.

So where does that leave us?

Revised Poison
Upon failing a save when poisoned, the PC loses 1 hit point/round (modified by save bonus) for each instance of poisoning. Slow Poison (or holy water) reduces that loss to 1 hit point/turn (when applied within 1 turn/level of the caster or 1 turn respectively). While the damage inflicted by poison can be healed, the effects of the poison continue until the poison is neutralized or the character dies. A character is incapacitated when they take more damage from poison than their Constitution (or, of course, reach 0 hit points). Non-magical neutralization of poison (character abilities, proficiencies, holy water) must occur within a turn of being poisoned. Magical poison reduction/neutralization can occur as long as the PC is alive, but will not heal damage received from poison.


The real failing of this revision is the ongoing nature, now having to track ongoing damage per round (or per turn). The potential to heal the damage likely drains the party’s ability to heal in a likely doomed attempt to keep the PC alive. To address this, have healing not work until the poison is neutralized.


TSR 2010, Players Handbook [1e], 1978.
Dragon Magazine, Issue 18 [1e], “Effective Use of Poison”, December, 1978.
TSR 2011, Dungeon Masters Guide [1e], 1979.
Dragon Magazine, Issue 59 [1e], “Poison The Toxins of Cerilon”, March, 1982.
Dungeons & Dragons. Expert Rulebook. 1983.
Dragon Magazine, Issue 81 [1e]. “Taking the Sting out of Poison”, January, 1984.
Dragon Magazine, Issue 32 [1e], “Poisons From AA to XX”, December, 1989.

Appendix – MM Poisons

Note that many things require a Save versus poison. The below are those that appear to be actual poisons, roughly 10%(not by rarity)

MM, Giant ant: 0, d4/death
MM, Centipede: +4. non/death
MM, Couatl: 0, non/death
MM, Orcus: -4, non/death
MM, Baalzebu: 0, non/death
MM, Erinyes non/faint d6 rounds
MM, Geryon -4, non/death
MM, Green dragon: 0, non/death
MM, Eel, weed: 0, non/death
MM, Frog, poisonous: +4, non/death
MM, Golem, iron: 0, non/death
MM, Imp: 0, non/death
MM, Manticore: 0, non/death
MM, Medusa: 0, non/death
MM, Naga: 0, non/death
MM, Pseudodragon: 0, non/catalepsy
MM, Purple worm: 0, non/die
MM, Ray, pungi: 0, non/death
MM, Ray, sting: 0, non/paralyzed
MM, Scorpion: 0, non/death
MM, Snake: non or 3d6/death
MM, Spider: +2 to -2, non/death
MM, toad: 0, non/death
MM, Wasp: 0, non/paralysis and death
MM, Wyvern: 0, non/death


Author: Rick

A DM for *mumble* years, I've been playing AD&D since junior high. I've currently got two separate campaigns running, both in Mystara. I've been told when they handed out hobbies, I stood in the short lines. I actively cycle tour, kayak, play board games, read, develop home automation software, play Stars!, volunteer with the International and National American Red Cross, and work on a never-ending stream of home repairs. In my wake I've left paintball, medieval full-contact combat (SCA), computer gaming, Heroclix, and kite construction.

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