AD&D Poison Notes

In Dragon magazine #81 (January 1984) the article "Taking the Sting Out of Poison" by author Chris Landsea offered truly exhaustive coverage of the topic of poison in AD&D, filling in many gaps and holes in the official rules. The rules in that article make poison much more interesting, both by providing more details for its use in the game and also some ways to mitigate its effects and make it feel less like a "screw you" when used in the game - especially with low-level characters who don't have access to magical means of neutralizing it. 

However, like many Dragon articles of that era, Mr. Landsea went overboard in presenting 10 full pages of text and 10 tables - too much of a good thing that adds so much extra complication to make things hard to remember and make use of in-game. Therefore, in order to strike a happy balance and achieve the best of both worlds, I've extracted and summarized (and revised) the essence of those 10 pages and 10 tables into a simpler and more user-friendly set of guidelines that allow the additional flavor and options introduced in that article to be incorporated into AD&D games without becoming overwhelming. 

This material is being incorporated into The Heroic Legendarium (which I promise is still going to be released - just as soon as I master the challenges of art and layout in order to transform a roughly-140,000 word Google Doc into a reasonably-professional-looking pdf and print book), but since this blog has been sitting idle for far too long, I figured there's no harm in sharing it here as well, as another preview-of-sorts of what that book will eventually contain:

AD&D Poison Notes

Blade venom: One dose of blade venom is sufficient to coat one melee weapon or up to four arrows, darts, or crossbow bolts. A character using an envenomed weapon has a 5% chance per round (check every round the weapon is in use) of nicking and poisoning him or herself, + or - the character’s reaction bonus for high or low dexterity (i.e. 2% for a character with 18 dexterity). This chance is halved for assassins (i.e. 2% for an average-dexterity assassin or 1% for an assassin with a 17 or 18 dexterity).

Poison Gas: Types are equal to ingestive poison Types A-D, but sufficient gas to fill a 10’ x 10’ x 10’ area costs 10 times more (i.e. 300 g.p. for a vial of Type B poison). Once the vial is opened or broken the gas will expand to fill the area in 1-2 rounds and remain effective for one turn before dissipating. Characters who make their saving throw against poison gas are holding their breath and do not suffer partial damage. Type E poison gas costs 1,000 g.p. per dose and has an onset time of 1-3 rounds but a failed saving throw causes sleep for 1-6 turns instead of damage or death.

Contact Poison: Types and effects are equal to insinuative poison, but only require contact with skin, not injection into the bloodstream. Contact poison retains full effect for one month, drops to 50% effectiveness for up to six months, 25% effectiveness for up to a year, 10% effectiveness for up to 18 months, and after that has no effect. For contact poison Types A-C this lessening of effect equates to reduced damage, while for Type D it equates to a +2, +3, or +4 bonus on the saving throw. One dose is sufficient to coat one regular-sized object (such as a weapon hilt, doorknob, chest handle, or bejeweled item) or up to a dozen coins or gems.

Monster Venom: Onset time for most monster venom is 1-6 rounds, however for venomous monsters with 5 or more hit dice the onset time is one round. An assassin trained in poison use has a 50% chance of being able to recover usable venom from slain monsters: one dose from a size S monster, 1-3 doses from a size M monster, and 1-6 doses from a size L monster. This recovered venom can be used by the assassin as ingestive or insinuative poison, or may be processed in a lab into gas or contact poison. Unprocessed venom retains potency for one week, but once processed it retains potency as per normal poison of its mode. The Assassin’s Guild uses recovered monster venom to manufacture other types of poison and does not sell unprocessed monster venom, so it always must be recovered directly.

Poison Antidotes: Antidotes to ingestive, insinuative, gas, and contact poison may all be purchased at the same price per dose as poison of the appropriate type. While poisons can typically only be purchased from the local Assassin’s Guild, antidotes may also be purchased from regular alchemists. Each letter-type antidote is effective against the corresponding type of poison and all lesser types of the same mode (i.e. Type D ingestive antidote works against Type A-D ingestive poison but not Type E or any non-ingestive poison). Antidote can be taken before the poison is administered and remains effective in the character’s system for up to three hours, or can be taken after the poison has been administered but before it has taken effect in order to neutralize the effect. An antidote taken after the poison has already taken effect will not remove or reverse any damage or effect that has already been inflicted. One dose of antidote will counteract one dose of poison. Antidotes to monster venom are specific to the monster type (i.e. giant scorpion antidote is not effective against giant spider venom or vice versa) and very expensive - the cost is 1,000 g.p. per hit die of the corresponding monster type (e.g. 5,000 g.p. for a dose of anti-giant scorpion venom), halved if the purchaser is able to supply a sample of the appropriate type of venom to the alchemist who is preparing the antidote. 

Use of holy water: In addition to its other uses (as a spell component and against the undead) drinking a vial of holy water will delay the onset of any poison by 3-9 (2d4+1) turns, and will even temporarily revive a character who has already succumbed to poison if fed to them within one turn of the poisoning (cf. slow poison spell). This effect only works once per poisoning (i.e. drinking a second vial doesn’t increase the delay) and unholy water does not have this effect.