Potion Miscibility
For my 5e game, I brought back the rule of Potion Miscibility. Way back in the AD&D days, if you just started chugging potions, bad- or cool- things can happen.
The world of d&d usually doesn’t have things like ingredient standards, many times the people making potions are those working over their cauldrons, or their own home alchemy set up. You never really know what’s going in to those hand-made potions. Unless you always get your same potions from the same alchemist, you might end up with some unfortunate side effects if you turn your own tummy in to an experimental cauldron.
I took the AD&D miscibility chart, the current miscibility chart and added my own twist to it, and sharing it here for all to see.
Potion of Healing - Common - 2d4+2- Rank Score 1 Potion of Greater Healing - Uncommon - 4d4+4 - Rank Score 2 Potion of Supreme Healing - Rare - 8d4+8 - Rank Score 3 Potion of Supreme Healing - Very Rare - 10d4+20 - Rank Score 4
1 Explosion! If two or more dissimilar potions are swallowed together, or too soon right after another, the drinker damage equal to the amount of dice and dice added using rarity equal to a potion fo healing. For example, an Uncommon Potion (4d4+4) + a Rare potion (8d4+8) would deal 12d8 +12 damage. All creatures within a 5ft radius must make a Dexterity saving throw or take half the damage dealt. If mixed externally, then all within a 10ft radius must make a Dexterity saving throw. Each rarity is given a score of 1 to 4, with 1 being common and 4 being very rare. The DC will be base 10+ First Rank + Second Rank. On a successful save, they take half damage.
02 - 10 Lethal Poison. Nether potion works. The drinker must make a Constitution save (DC 10 + First Rank Score + Second Rank Score) or die. If the save is made, the drinker takes half 6d10 damage. If the damage is enough to take the drinker to death, they instead fall unconscious with 1 hp. If mixed externally, then a cloud of poison envelops the area of a 10ft radius and everyone must make a Constitution saving throw. On a successful save, they take half damage.
11- 20 Mild Poison Neither potion works. The drinker suffers a point of Exhaustion, and 3d10 damage. On a successful saving throw (DC10+First Rank+Second Rank) the drinker negates the damage, but not the Exhaustion. If mixed externally, a cloud of gas envelops the area in a 10ft radius and all within must make a successful DC saving throw or take 3d10 poison damage.
21 - 25 Potions cannot be mixed The drinkers race is abruptly transformed. At random, the drinker becomes a random humanoid race for a number of days equal to the rarity of the potions added. A Remove Curse spell will transform the drinker back to their normal form.
26- 30 Cursed Neither potion works. Instead, the potion acts as a Bestow Curse spell, with the effect chosen at random at the DMs discretion, and has a duration of a number of days equal to the added Rank score of the potions.
31 - 35 Hostile Monster Summoned Neither potion works. Instead, the drinker vomits a black acrid cloud of smoke, which solidifies in to a monster. The monster is chosen at random from the Monster Manual, with a Challenge Rating equal to the added Rank Score of the potion’s rarity. For example, an Uncommon and Very Rare potion (Rank 2 + Rank 4) would summon a monster with a challenge rating of 6. (Chimera, Wyvern, Medusa...)
36 - 45 Potions cannot be mixed Both potions are totally destroyed and fail to function.
46 - 55 Potions can be mixed They both work normally, unless the effects would cancel each other out, then only the potion of lower rarity works.
56 - 65 Potions cannot be mixed The potion of the higher rarity immediately has the opposite effect, while the lower rarity ceases to function. If the effect of the potion would cause the drinker to die, they are instead rendered unconscious at 1hp.
66 - 75 Potions cannot be mixed The drinker rapidly begins to change color at random, blue to green to yellow to pink and through all visible colors. The drinkers color settles and stops on random color, and remain that color for a number of days equal to the potions rarity scores added.
76 - 85 Potions can be mixed, but not as expected. Neither potion works, but both turn in to another potion equal to the highest rarity, as chosen at random by the DM.
86 - 99 Compatible Results The potion of a higher rarity effects are doubled for twice the duration, the second potion fails to work.
100 Discovery The mixing of potions creates a special effect, one potion, at the DMs discretion, fails to work, but the other has it’s effects made permanent on the drinker, in the simplest form as chosen by the DM. A Remove Curse, or Dispel Magic spell may end this effect at the DMs discretion.
