Poisonous Herbs of the Realm

Poisons are brewed in the exact same way as Healing Herbs. However, when utilizing the poison, the creature targeted by the poison must succeed at a Constitution check at a DC that is equal to the DC used harvest the herb. +1 for each additional hour spent making the poison.
If the target succeeds at its check, any immediate damage is halved. The target does not suffer any other effects, whether immediate or ongoing. If the target fails its check and the damage is per round or ongoing they continue to make a save on every turn until they are incapacitated. If they have the Poisoned condition, they are at disadvantage for their saving throws. Their death saving throws are at disadvantage.
Weapons coated in a poison must still succeed on a hit before the effects will apply to the target (after a save). Each dose will only activate once per application. You can apply multiple doses to a weapon and each dose will activate on a separate hit.
The saving throw for all poisons made this way is always constitution, regardless of whether the effect may call for a different save.