The PHB states that poisoned creature has disadvantage on attack rolls and ability checks, and that poisoned weapons do extra ‘poison’ damage.

But in this world there are a wide array of poisons that can have various effects, and an expert poison expert can take advantage of that. Poisons are crafted from reagents of which there are many types.


base reagents:

a base reagent is always a poison or venom in itself. It MUST be harvested from a creature (such as the venom of a rattlesnake or the skin of a poisonous frog).

type/effect reagents:

a type/effect reagent does not have to be a poison or venom. It can be harvested from a creature, a herbal source or alchemical source. Adding a type/effect reagent can add a damage-type (such as acidic if using the essence of a grey ooze), or condition effect (such as paralysis if using the beak of a cocktrice). Only harvested creatures, herbs and alchemical sources which have a damage-type or can cause a condition effect can be used for a type/effect reagent.

augmentation reagents:

an augmentation reagent improves a poison’s damage, effectiveness or both. It does not have to be a poison or venom. It can be harvested from any creature, herbal source or alchemical source.

Poisons can be crafted from 1 base reagent, 1 base reagent and 1 type/effect or augmentation reagent, or all three reagents.

Harvesting reagents

A player must use a Nature or Arcana check (DM’s discretion depending on the source) to harvest a reagent.

Harvest DC = 10 + reagent’s Challenge Rating Modifier (CRM)

Succeeding the Harvest check by 5 gives 2 usable amounts of reagent and rolling a natural 20 gives 3 usable amounts. The time to harvest is the creature’s Challenge Rating (CR) in minutes.
The reagent’s Challenge Rating Modifier (CRM) is dependant on the creature’s Challenge Rating (CR):

Reagents can also be bought from unscrupulous suppliers. The same equation can be used to harvest a one shot use of a creature’s poison without crafting, however there are downsides to this: only 1 dose of the poison can be harvested regardless of the roll, it will never be as potent as the poison being properly crafted, and the Save DC is much lower (snake venom on a blade is not delivered as effectively as snake venom directly from snake fangs). The difference is between milking a dose of venom from a recently dead snake and harvesting the venom gland which can be used to craft multiple doses in a concoction that is more suitable for an assassin’s delivery. The player must declare before the harvest roll whether they intend to harvest for crafting or an immediate one shot use.

Harvesting herbal or alchemical reagents is at the DM’s discretion. A table for the CRM of herbal and alchemical reagents can be found here (TBD).

Crafting poisons

The player must make an Intelligence Check:

Crafting DC = 8 + Base Reagent CRM + Type/Effect Reagent CRM + Augmentation Reagent CRM

There must always be a Base Reagent, the rest are optional. Proficiency in poisoner’s kit and access to one allows the player to add their proficiency bonus their Intelligence Check. Players without the poisoner’s kit proficiency have a 50% chance of poisoning themselves with any or all of the reagents if they roll below a natural 5. The DM may always increase the Crafting DC for ingame context.

The crafting time is 10 x Crafting DC (minutes). The crafter is then mentally exhausted for the same amount of time afterwards and rolls intelligence based saving throws and skill checks at disadvantage for that duration. Crafting in downtime can avoid this penalty, but then the crafting time is Crafting DC (hours).

Creature’s affected by the crafted poison make a Constitution saving throw vs the Save DC of the crafted poison. See Save DC below.

Base Reagent Damage

A poison crafted from only a base reagent will only do damage and not confer any type/effects or augmentation benefits (such as the poisoned condition, etc.) Hence a player should always be on the lookout for venoms and poisons for they base of their crafting, more exotic reagents with interesting effects would be better suited for other adding to a base reagent. For Creature CR’s over 8 the crafter can choose to have a consistent damage or a volatile poison which can do very high or very low damage.

Damage Types & Condition Effects

A crafter that adds a type/effect reagent can add a new damage type to the poison, although the resulting poison will retain the damage type ‘poison’ as well as the new damage type. A type/effect reagent can also be used to confer a condition effect such as ‘sleep’, if the creature or herbal/alchemical compound is known for this condition. Only 1 type/effect reagent can be used and the crafter must choose whether the reagent is used to confer either a type or an effect if the reagent has the possibility of either.


An augmentation reagent allows the crafter to roll an Augment Die in the crafting process, the result of the Augment Die can give the poison extra damage, increase the Save DC, apply the ‘poisoned’ condition, give half damage on a save, do reoccuring damage indicated by { }, or even overcome poison immunity/resistance. Which Augment Die is rolled depends on the CRM of the augmentation reagent:
Proficiency with poisoner’s kit allows for a reroll of an Augment Die of d8 or less that lands on “No augment”.

The Augment Die is then represented by the letter B in the augmentation damage tables below:
Screenshot_2020-08-19_at_00.18.01.png Screenshot_2020-08-19_at_00.18.22.png

Screenshot_2020-08-19_at_00.18.55.png Screenshot_2020-08-19_at_00.19.11.png

Save DC

A creature subjected to the crafted poison must make a Constitution saving throw vs the Save DC of the crafted poison:

Save DC = 8 + Base Reagent CRM + Augmentation Reagent CRM + Your Intelligence modifier + Your Proficiency Bonus if proficient in poisoner’s kit

(Notice how the type/effect reagent CRM is not factored here.)

Use in combat and skulduggery

Before crafting the player must announce whether they are crafting a poison to be ingested or for applying to a weapon: once a poison is crafted its purpose cannot be changed and will only work as intended when crafting.

A single use of crafted poison applied to a weapon is effective for one minute or until the target is struck. For ranged weapons a single dose can be applied to one piece of slashing or piercing ammunition.

Herbal and alchemical reagents

Herbal and alchemical reagents can be used as type/effect reagents and augmentation reagents. Herbal reagents are particularly well suited for confer effect conditions and alchemical reagents can do ability damage as their effect; both can introduce offset times which delay the effects and in rare circumstances can cause death.

Just as a snake’s venom can be harvested for a one shot use, so can herbal and alchemical reagents be harvested in this manner for one raw use, such as hemlock or arsenic. The main difference is that herbal and alchemical poisons used without crafting must be ingested in order to have any effect, but even poisons to be ingested do better when crafted.

There is one exception to requiring venom or poison harvested from creatures as base reagents: alcohol can be used as a base reagent (the CRM for crafting is 1). However, using alcohol as a base reagent means that only 1 type/effect reagent can be added (no augmentation), the type/effect reagent must be herbal or alchemical and the poison can only be ingested. Notice that in this case the Save DC is very much dependant on the crafter’s intelligence.

A table for the effects of various herbal and alchemical reagents can be found here (TBD).

These poison rules are a slight adaptation of the Poison Crafting: Revised Rules by Jonathan Chia, which can be found at the DMSguild.


Gaxim Plague Frak_Lou_Elmo Frak_Lou_Elmo