Crafting Antivenom

While antitoxin presents a generalized tool for protecting oneself from poison, more specialised antivenoms can provide even greater protection against specific poisons. Creating a dose of antivenom requires a dose of the specific poison that the antivenom is designed to protect against.

Antivenom Effects

A single dose of antivenom automatically neutralises the first exposure of the specific poison it is made to combat and imparts disadvantage on poison attacks resulting from additional exposure to that specific poison; this bonus ends after 1 hour.

Crafting Antivenom

To create a dose of antivenom, a living creature must first be exposed to a half dose of the poison in question. The creature suffers the poison’s effects normally, except the poison’s attack bonus is reduced by 2. In order to be able to produce antivenom, the creature must be missed until it is cured of the poison. If the poison’s duration expires without the creature being cured, no antivenom can be harvested.

Once the creature has resisted the poison’s effects, a viable sample of the creature’s blood can be extracted with a successful DC 20 Alchemist’s supplies or Wisdom (Medicine) check. This blood must then be refined to extract the natural antibodies that combat the poison in a process that takes 1 hour and requires a successful posioner’s kit check (DC = 15 + the poison’s attack bonus). Success yields 1 dose of antivenom.

Antivenom can also be harvested in the same fashion from a creature that has been afflicted by a full dose of poison, rather than a creature deliberately given a half dose for this purpose. Regardless of how much poison the creature is exposed to, the antibodies in its system can be harvested only for 24 hours after it has recovered from the poison.

Purchasing Antivenom

Antivenom is not particularly expensive, but because it is highly specialised, it can be difficult to find. A dose of antivenom has a market price equal to half the market price of a dose of the poison in question, but it is treated as though its price were five times the market price of the poison for the purposes of determining its availability in any given settlement. Alternatively, if 1 or more doses of the poison in question can be provided, most alchemists will supply as much antivenom as they can produce from the doses for a fee of 10% of the market price of the poison.