Poultice
A soft moist mass about the consistency of cooked porridge that is spread on cloth and applied warm to create moist local heat or counterirritation.
As in: 'And silence, like a poultice, comes/ To heal the blows of sound' by Oliver Wendell Holmes, Sr.
The word poultice derives from the Latin pulta and the Greek poltos, both meaning porridge.
Also called a cataplasm