Lands of Algia 4E
One moment, your victim is all smiles. The next, it keels over and dies.
Power (Consumable * Poison): Minor Action. Effect: You sprinkle the poison into a drink or onto a plate of food. Until the end of the encounter, the first creature to consume that food or drink is subject to the following attack.Attack: Item’s level + 3 vs. Fortitude. Hit: There is no effect for 1d6 hours. At the end of this time, the target takes ongoing 5 poison damage and is dazed (save ends both). Published in Dungeon Magazine 186.
Found in the main chamber of the Temple of Nerilous