For the version used against the Penance King, see Poisoned meat (Penance King).
[FAQ] • [doc]

Poisoned meat is used in Barbarian Assault to hurt penance healers. The healer needs to use the poisoned meat on the penance healer, and it will poison the monster.

Poisoned foods were previously not stackable, but they were made stackable (and taken in a stack of 50) in the 26 August 2014 update.