Inspiration Strikes - Handling Poison

Ch-click! The stone surface depressed slightly underneath the halfling's foot. Just as that fact made itself known to the footpad's mind, a row of small needles sprang from the floor, piercing the boot and puncturing Lightfinger's foot! 

"OWWWW!" he cried as he backed up. "Something got me!"

Then... he felt a wave of nausea sweep over him. Bile rose in his throat as his limbs felt weak.

"Guys... I don't feel so good..."

Poison is one of those topics that every DM has thought about. Sean over at TheCampaign20xx blog has a great summary of D&D's published poison rules across the editions.

I'm a fan of things giving players pause. I remember the look on my player's face when he had to save vs. Death because of poison from a Chaos creature - this was a 4th level paladin! There had been plenty of foreshadowing about these creatures, but the frisson of the moment was palpable to all eight of us at the table! (He used the d30 rule [1] and survived.)

We play to live, knowing that we can die... but dying from the poison of a 10 year old trap or a Giant Centepede? There are times when I want something different.

Thus, when Lightfingers hit a trap during a recent delve into the infamous Quasqueton dungeon, and failed his save, I thought about what the result should be. Death, and lots of laughter and a quick six 3d6 generation? Or do something more fun, giving this character a different fate?

I opted for the latter. RAW OD&D (as per the original 3 books) has an interesting bit regarding Constitution (pg 11) - "Constitution 13 or 14: Will withstand adversity. Constitution 9 - 12: 60% to 90% chance of surviving. Constitution 8 or 7: 40% to 50% chance of survival"

Oho! This poison trap gave me a chance to use that bit. I rolled to see when the poison's effect would require him to test his "chance of survival" (. i.e., a system shock!) and it was 6 turns. During that time, his move dropped to 3", he was at -4 for melee/missiles/saves.

At 6 turns, he failed his "chance of survival" check and he took a d6 of damage from the poison.. Another d6 said he had to check again in 4 turns. He was still at his "poisoned" penalties. After those 4 turns, he rolled his check. He was no longer sick, but the hp loss remained, subject to any healing that might be found in the dungeon.

For my game, this was more fun and generated quite a bit more caution out of the PCs. They had the chance of somehow finding something to help Lightfingers, or hope that he recovered, or wondered if he would die. I wanted that kind of game better more than "BLAM, you're dead, reroll". (those games are absolutely appropriate and great fun!)

From that bit of in-game inspiration, I came up with this sort of approach for future use:

Alternative Poison Rule

For poisons of creatures of less than 2HD, for many contact poisons and some (weak) ingested poisons, make a save vs. poison. If they fail:

  1. Victim is penalized -4 on melee/missile to-hits and other saving throws.
  2. A d6 determines how many turns elapse before the PC must make a "Constitution survival (system shock) check". (OD&D: CON of 6 or less, AD&D: Con of 5 or less: 0% chance).  If the PC has a 13+ con (OD&D), or 15+ con (AD&D), the effects wear off after this initial period of illness with no hp loss or further penalty.
  3. A failed survival check means the poison does d6(OD&D) or one half of  2 to 4d10(AD&D, DMG pg 20 lays out the different classes of poison) hp damage. Another d6 is thrown to see how many turns elapse before the next check.
  4. A successful check means that the victim is able to withstand the effects of the poison and no longer suffers from the penalties or damaging effects. Any lingering effects is up to the DM!
  5. Poison hp loss may be cured at anytime, even while the victim is sick, but said curing does not remove the effects of poison! Only antitoxin/antivenom, or some magical means that removes poison, will heal the victim of the poison's effects.

For creatures of 2+HD or virulent/strong poisons, the "save or die" rule applies, unless other effects are noted for the poison.

For me, this is a nice little subsystem that uses Constitution and hp in ways that make sense to me. It is possible that one may indeed die from poison, but at least there is a 1 to 6 turn time period which they desperately search for a means of survival. It might not necessarily be "simple", but it's something I could play now and again, for a bit of variety to how poisons work.

Game on!

[1] The d30 Rule:  If, in the perilous moment of fate and before the hand of the GM hath cast the selected dice, thou wishest to chance thy fate on the great black and red d30, thou mayest do so. Thee must declare thine wishes prior to the cast of fates. Once the d30 hast been cast, thou must live with thine fate as decreed. Only once per game may thou chooseth the d30. Thou are prevented from using the d30 to determine thy starting or additional hit points.


  1. Hello! Could you explain how step 2 of your alternative poison rule works? I'm not familiar with editions after B/X; is a constitution survival check simply trying to roll CON or else on a d20? And what exactly are the benefits of the 13+ or 15+ CON? Please excuse my ignorance; this is probably obvious to experienced players.

    1. Hi Greg!

      Sure, in OD&D (and AD&D), there is the concept of a "system shock" test. OD&D called it "survival check" and gave hints that it should occur to see "how well the character can withstand being paralyzed, turned to stone, etc.".

      AD&D went into more details and added an extra check for being raised from the dead or resurrected, but also kept "system shock".

      It's a d100 check, roll under.

      For OD&D, the rule is that if a person has a 13 or better constitution, they will "withstand adversity" - they automatically make a system shock/resurrection check. (In AD&D, that's not the case anymore, but the percentages are high 85% system shock, 90% resurrect, and they go higher for each point above 13.)

      So, when someone in my OD&D game is poisoned and it is NOT a "save or die" type of poison:
      1. They become violently ill for d6 turns. All combat is at -4.
      2. If the person has a 13 or better CON, that's it. Once they pass that initial sickness, their constitution is hardy enough to throw it off and they move on with life.
      3. If the person's CON is lower than 13, they have to roll a d100.

      I think, for 3.5e and later, it's some sort of a saving throw based on the constitution. For 5e, you would have to go against a "DC" (Difficulty Class) of the poison, adding in the bonus/penalty from the attribute affected - so in this case, poison would most likely affect CON.

      That is what Step 2 is about. Hope that helps to clarify.

  2. Thanks! BTW, I heard your appearance on the Hobbs podcast and much enjoyed it. I don't actively play D&D anymore, but I enjoy hearing about what's going on in the OSR.

    1. Thanks, Greg. I had a lot of fun being a part of Jason's podcast.

      If you're interested, I host a podcast mainly about my old school D&D campaigns - called Dungeon Master's Handbook. The link is:


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