Poisons

Poisons in AD&D are divided in various classes, depending on the effect and how they are to be used. This table is at pag. XX of the Dungeon Master Guide. For these detailed rules a new skill is introduced, the Poisons skill, which is of the Rogues group, costs 3 non-weapon proficiencies and is based on Intelligence. If you use the optional rules on proficiencies from Player's Option Skills and Powers, the proficiency costs 5 points, has as a starting value of 6 and is based on Intelligence/Knowledge and Wisdom/Intuition. Animal poisons can't be reproduced, but they can be extracted from the animals and treated so that they don't degrade at the air with a Poisons roll (or another appropriate skill, with a malus at DM's discretion). These poisons are usually to be injected. They can be treated to put them on weapons, but in this case the victim will have a +4 to ST and the effect will be halved. If the poison causes death, the fictim will instead suffer 1d6 HP per monster's HD. With one monster, one dose of poison every 6 HD (1 dose minimum) can be produced: most poison is lost during the extraction. Those in the table are vegetal poisons, which can be produced with a Poisons roll.

To make poisons a lab is needed, costing 1000 GP. Any character can make vegetal poisons with a Poisons roll with a malus equal to the difficulty. This and any other Poisons roll regarding vegetal poisons can be substituted by a Herbalism roll with a -2 malus. If the roll fails, the ingredients are wasted. To make one dose of poison, it takes a number of hours equal to 6 times the difficulty (minimum 1 hour). There are many herbs that can be used to make the same poison, in a way similar to magical potions. On the table there are only general guidelines. Contact poisons can be placed on weapons without penalty and injection poisons with the same penalties as the animal poisons. Both for vegetal and animal poisons, one dose lasts for one successful blow.

Making antidotes is done with a Poisons roll, with the same rules as per making the poison and the same difficulty. The antidote must be administered in the same way and grants a new ST of 5 (if the normal one isn't already better) against the poison. If the ST is passed, the onset is doubled and only the minor effects are sustained. In any case, the victim doesn't die: if the minor effects would kill him or her, he or she is left with 1 HP and weak for one day for every HP below zero. To identify a vegetal poison by the symptoms, a Poisons roll is required with a -1 penalty for every uncommon or rare herb used. Common herbs can be found almost anywhere and can be found with a Poisons roll with a penalty equal to the difficulty in 2d3 hours. Uncommon herbs can only be found in specific places. The help of a sage is required and the character must go there and make a roll as for the common herbs. Rare herbs only grow in very few places in the world. An expert sage must be contacted and reaching the place can be hard.

CLASS	METHOD	ONSET	POWER	PRODUCTION	ANTIDOTE
A	Injection	10d3 round	15/0	1 common herb, diff. 0	1 common herb
B	Injection	2d6 round	20/1d3	2 common herbs, diff. 0	1 common herb
C	Injection	1d4+1 round	25/2d4	1 uncommon herb, diff. 2	2 common herbs
D	Injection	1d2 round	30/2d6	1 rare herb, diff. 3	1 common herb
E	Injection	Immediate	Death/20	2 rare herbs and 5 uncommon, diff. 5	None
F	Injection	Immediata	Death/0	2 rare herbs and 3 uncommon, diff. 5	None
G	Ingestion	2d6 hours	20/10	1 common herb, diff. 0	1 uncommon herb
H	Ingestion	1d4 hours	20/10	1 common herb, diff. 0	1 uncommon herb
I	Ingestion	2d6 round	30/15	2 common herbs, diff. 1	1 rare herb
J	Ingestion	1d4 round	Death/20	2 rare herbs and 3 uncommon herbs, diff. 5	1 rare herb
K	Contact	2d4 round	5/0	1 uncommon herb, diff. 2	1 common herb
L	Contact	2d4 round	10/0	1 uncommon herb and 1 common, diff. 2	1 common herb
M	Contact	1d4 round	20/5	2 uncommon herbs, diff. 3	2 common herbs
N	Contact	1 round	Death/25	3 rare herbs, diff. 7	2 rare herbs
O	Injection	2d12 round	Paralysisi	2 uncommon herbs, diff. 3	2 uncommon herbs
P	Injection	1d3 hours	Weakness	1 common herb, diff. 1	3 uncommon herbs

Mineral poisons have similar effects and can be made in the same way, but they can only be made with Poisons rolls (not Herbalism), with another -2 malus, and various minerals and exotic substances are used instead of herbs. The ST given by an antidote isn't 5 but 8. The cost of a poison or antidote should be about 100 GP for each rare herb used, 10 GP for each uncommon herb and 1 GP for each common herb. Mineral poisons cost twice as much. A character with a high (16+) skill in Poisons can research new substances with different effects, such as sleep, paralysis, loss of characteristic points. This skill, anyway, doesn't cover the making of drugs and isn't of help in making potions.
The player and the DM should decide the ingredients and effects of the new substance. To research a new poison, a character must have a lab worth 5000 GP, and must spend 1 month for each rare herb used, one week for each uncommon herb used and one day for each common herb while experimenting. He spends in ingredients ten times the final cost of the poison. After this period, he must make a Poisons check with a malus equal to the new poison's difficulty, plus another -2, and if he succeeds he has the first dose of his new substance. If he fails, he can try again after having spent in the lab 25% of the time calculated before (and spent 2,5 times the poison's final cost), and he has a +1 bonus, stackable, until he succeeds.