If a person or an animal foams at the mouth, they have bubbles coming out of their mouth as a result of a disease.

He was having convulsions and foaming at the mouth.

They found her on the ground, foaming at the mouth.

Some rabid animals will foam at the mouth, but most do not.

The animals were in a terrible state, lying in their own dirt and foaming at the mouth.

The dog was snarling and foaming at the mouth.

See also: foam verb