Creating a poison with non-damaging effects, called a toxin, does not follow the rules for normal poisons. They’re brewed like a normal potion except only spell effects with the toxin attribute can be used when brewing the toxin in question.
However, these more complicated compounds lose their bite much more quickly than their simpler counterparts when applied to weapons or ammo, lasting for 1 minute (10 rounds) or 3 successful hits with the weapon/ammo, whichever comes first.
Characters that take damage from a weapon poisoned with a toxin use Endurance for any characteristic tests required by the toxin’s magical effects.