Question

Foam at the Mouth to be uncontrollably furious, like a mad dog

Accepted Answer

Dad was foaming at the mouth when he found out that Jerry had slipped out of the house. A dog with rabies or distemper foams at the mouth. A bubbly saliva forms around the lips, and the dog behaves in a crazy manner. As long ago as the 1400s people began describing furious people as "foaming at the mouth," as if they were mad dogs.

Idiom	Foam at the Mouth
Example	Dad was foaming at the mouth when he found out that Jerry had slipped out of the house.
Meaning	to be uncontrollably furious, like a mad dog
Origin	A dog with rabies or distemper foams at the mouth. A bubbly saliva forms around the lips, and the dog behaves in a crazy manner. As long ago as the 1400s people began describing furious people as "foaming at the mouth," as if they were mad dogs.

Dog Mouth Mad People Foam Dad Foaming Found