Typically poisons range from instant death (as found in the Dungeons and Dragons game) and the simple 1 point of damage per round (as found in video games like the Ultima series). These are both very simple, but don’t provide a wide range of possible outcomes. Some games have cumbersome charts that still have their limitations. And there is the matter of whether or not you want to randomly roll what a poison does. Instead we might be able to come up with some concepts that allow a DM to create a poison that’s appropriate on-the-fly.
Properties of Poison
Poisons have 4 or 5 properties in terms of game mechanics.
- Saving Throw: Adjustment to saving throw is generally an indicator of the poison’s strength. (Suggested range: +4 to -4.)
- Incubation Period: The time before poison takes effect can also be determined by how powerful you think the poison should be, or how fast it reaches the bloodstream (breathing, ingestion, injection, etc.) (Typical ranges: 1 day to instantaneous)
- Duration: This is the time the poison takes to run its course, after the incubation period.
- Effect: The effect of the poison can be damage, penalties to rolls, and any other quantifiable modification to game play. Effects should be used with the next optional category “appearance” for the best game play.
- Appearance: This is how the poison affects the non-quantifiable modification to game play. This is somewhat optional, but can include things like sores, vomiting, or anything else which can be part of the story, but doesn’t really affect the numbers of game play.
Poison Creation
DM: You step on a block that depresses; a dart shoots out of a crack in
the wall and hits you. Make a saving throw vs poison.
Player: I rolled a 10.
DM: You can't feel any effects.
game hours later...
DM: The ogre misses you. Suddenly your arms feel strange and are becoming
numb. All your muscles are getting slower.
Player: Hide in the shadows around the corner in the hallway.
DM: You try to get out as quickly as possible, leaving to the protection of
the corridor. You become paralyzed. You hear the ogre coming towards
you and hope that you hid well...
As you can see from this example, the player wasn’t sure he had been poisoned, and the effects did not occur until later. This kind of situation could be very interesting and fun with other players to help out, but care must be taken not to let it ruin the game. This gives characters a chance to be cautious and makes antidotes and spells like neutralize poison more important.
The DM in this situation can easily create a poison ahead of time, or on the spot. The DM may want to make some charts for quick reference such as the ones below:
Simple Chart
This chart is a simple chart that contains weak, moderate, and strong poisons that do damage. This is particularly good for a DM who wants to give the players a chance to use their antidotes once the poison sets in.
Save Bonus Incubation Duration Damage
----------- --------------- ------------- -------------
Weak: +1d4 1d6 hours 1d8 hours 1d4 per turn
Moderate: 0 1d4 turns 1d6 turns 1d2 per round
Strong: -1d4 instant 1d10 turns 1d20 per round
Effects Chart
This is a chart for the kind of DM who wants to give poison more “flavor.” Yum. You can use the chart above to supplement the results, or determine the missing pieces on your own.
1d6 Incubation 1d12 Effect Appearance
--- ------------- ---- -------------------- ---------------
1 instantaneous 1 -1 to combat rolls pain
2 1d8 rounds 2 -1 to hit, +2 to AC numbness
3 1d6 turns 3 partial paralysis paralysis
4 1d4 hours 4 -1 to hit, 1/2 CHA sores
5 2d12 hours 5 1/2 STR, +2 AC weakness
6 1d6 days 6 -1 hit rolls, saves mild sickness
7 1/2 move, no actions violent sickness
8 comatose sleep sleep
9 1 dmg per round poisoned
10 1d4 dmg per turn poisoned/sick
11 1d10 dmg per hour mildly sick
12 5d6 dmg per round death
Many years ago, when playing FRPGs more regularly than I do now — and also studying chemistry — I too decided to fix up the poisons rules. However, I think you may have missed an opportunity for considerable simplification.
Fact is, healer / herbalist types in most pre-industrial cultures may have known about dozens of plant based poisons, but they rarely knew more than one or two that were really powerful. Most can only be taken in food because they are not powerful enough to kill at the sort of doses that can be applied on a blade. There are many, many poisons of this type, and if it rocks your boat you can really go to town with specifying dozens of examples, but they are rarely important in a FRPG. Most plant based poisons also won’t be effective in ancient traps in tombs because they break down within a couple of years (or sometimes, within days.) And only a very, very few are fast enough acting to be useful in combat. So I broke poisons down into just 4 main classes, which I describe using your system. (All listed ability damage is temporary, as per the usual rules, except where noted or if death occurs first!)
You will notice that a) all of them, being based on real poisons, are much slower than tyical FRPG poisons; and b) they are generally also much more damaging.
1. Mineral poisons: Very stable poisons that can remain potent in a trap for centuries. Based on a real poison that was fairly well known in mediaeval and Renaissance Europe. Lethal dose is about 3 grains.
Description: crusting of fine white powder stuck on the blade with some binder; sharp metallic taste followed by soreness in the part that touched it.
Saving Throw: +1d4 (many people have a mild tolerance.)
Incubation: 1d4 hours (although it immediately causes pain in the wound and irritation in the surrounding skin)
Duration: 1d4 days
Effect: -1d4 CON / day, death through heart failure if CON reaches 0.
Appearance: Headache, vertigo and nausea; progressing to jaundice (yellowing of the skin), exhaustion, & severe shortness of breath.
2. Typical arrow poisons: while common in legend, only a handful of real ones exist. This example is based on one which was actually used in Europe, China and India, mainly for hunting (it is too slow to be really effective in combat):
Description: A lethal dose is nearly invisible on a blade. Extremely bitter taste, causes numbness to lips.
Saving Throw: -1d4
Incubation: 1d6 minutes
Duration: 10d6 minutes
Effect: -1d4 STR / 10 minutes, commence drowning dmg when STR = 0 (total paralysis, including chest muscles).
Appearance: A numbing, tingling sensation starts near the wound site and gradually spreads outwards. Death is eventually due to cardiac arrest or respiratory failure.
3. “Instant” arrow poisons: one major reason that poisoned weapons have never been popular is that there are very, very few poisons that work fast enough to actually be useful in melee combat. None at all were known in mediaeval China or Europe. As such, these “instant” poisons should be considered very rare, exotic and expensive. The example below is based on a real one from South America; it is one of the fastest acting poisons known, and note that it still isn’t actually “instant” at practical arrow dosages:
Description: minimum lethal dose is invisible. Crude form appears as milky sap.
Saving Throw: 0 (Just to give the suckers an even break; in reality, you don’t survive this unless a friend has the antidote.)
Incubation: 4d6 rounds
Duration: 1d4 hours
Effect: -1d10 STR / round, commence drowning dmg when STR = 0 (total paralysis, including chest muscles).
Appearance: No other effects, but the sensation of paralysed breathing muscles is terrifying.
4. Typical plant based poisons added to food: here you can really go to town. There are literally thousands of plant based materials, and a few animals, that will make you deathly sick or dead if you eat them, so the DM can wax lyrical on the precise effects. I like to include some special FRPG effects, e.g. if a poison causes visual disturbances, what does it do to Dark vision? If it causes delirium and confusion, what does that do to spell casting? At any rate, you should bear in mind:
a) all but the most potent need several spoonfuls somehow slipped into someone’s dinner;
b) most taste absolutely awful (probably an adapation to stop you eating them accidentally), so they need to be masked with strongly flavoured foods;
c) *NONE* of them work quickly, and many take days to kill.
The example below is based on a poison used in many real life murders, possibly including the assassinations of several emperors, popes and tsars. One advanatage for the assassin is that, unlike most plant based oral poisons, it actually tastes nice.
Description: about an ounce of pulped vegetable, off-white with a very faintly greenish hue. Smells slightly of honey.
Saving Throw: 0
Incubation: 4d6 hours (no precursor symptoms at all.)
Duration: First phase, 1d4 days. Second phase, 2d8 days.
Effect: +2 penalties to targets due to illness in first phase. -1 CON per day in 2nd phase. If victim survives, 50% of this loss cannot be healed naturally.
Appearance: First phase, stomach pain, vomiting and diarrhoea. The victim then appears to get better for about a day, but then begins to suffer diarrhoea, jaundice (yellowing of the skin), and headaches progressing to delirium, seizures, then coma, and finally death.