Optional Variant Rule: Administering Poisons

The basic rules outline a few ways poisons may be administered but are relatively dull and lack meaningful differentiation. This optional rule replaces those rules in favor of a more dynamic approach that gives both game masters and players more options when they want to explore the depth of poison in the game. Regardless of how the poison is administered, each dose can only be used once.

• Ingested. This type of poison must be consumed, for example, as a drink or as part of a meal. These poisons are typically tasteless and odorless, though a perceptive creature may still identify some telltale signs of the poison. This requires a successful Wisdom (Perception) check, with a DC equal to 12 + the poison’s potency (maximum of 30 on a success, the creature can spit out the food or drink before any ill effects occur. Once ingested, the poison takes 1d6 hours to work its way into the bloodstream, at which point its effects begin.

• Contact. These poisons are absorbed through the skin and other membranes, like those around the eyes. They must be applied directly to the target’s skin or placed somewhere in hopes that it is touched. While it is on a surface, such as a banister or a table, it can be seen with a Wisdom (Perception) check, with a DC equal to 10 + the poison’s potency (maximum of 30). Once successfully applied, the poison takes 3d20 minutes to begin taking effect. If a creature has one-half or fewer of their hit points remaining when they touch the poison, it only takes 1d10 minutes to start taking effect, and they have disadvantage on all saving throws against that poison.

• Inhaled. These poisons are spread by throwing a vial or other container that explodes into a cloud of gas. The cloud size is determined during the crafting process but can be up to 15 feet. A creature in the cloud can use its reaction to make a Wisdom (Perception) check; if the result of the check is at least equal to 8 + the poison’s potency (maximum of 30), the creature may use the same reaction to hold their breath. The poison lingers in the air where it originally was for up to 15 minutes, though a strong breeze will blow it away. If a creature inhales the poison at any time (including by failing to hold their breath immediately), it takes effect in 1d20 seconds.

• Injected. These poisons must be directly injected under a creature’s skin to go straight into the bloodstream. The most common sources of these toxins are creatures with fangs or stingers, or individuals who are enterprising enough to adapt those creature parts into their own weapons. Weapons that deal piercing damage can be coated in this type of poison, but unless it was specially made to deliver poison, the target has advantage on saving throws against it. If a creature is successfully injected with one of these poisons, the effects begin instantly.

Source: DM Lair - Poisons Explored