Foaming At The Mouth


The phrase foaming at the mouth is an idiom people use to describe someone who is very angry; to be furious.

Example: While heading to work, I honked my horn at someone because they were driving too slow. They were foaming at the mouth afterwards, as they slammed on their brakes, got out of their car, and started shouting at me. I quickly left the situation before things escalated.​

1. Having a chip on your shoulder
2. Having a bone to pick
3. Seeing red
4. Up in arms

The Origin Of ‘Foaming At The Mouth’

This phrase likely originates from a virus called rabies, as it can cause literal foaming at the mouth for the animal that’s infected with it. Rabies is a deadly virus that both humans and animals can catch. This virus generally spreads through a bite from an infected animal, like a bat. One symptom of rabies is that it makes swallowing very difficult. Consequently, saliva builds up and there is a ‘foaming’ at the mouth.

This expression is at least over 400 years old. For instance, in 1601, William Shakespeare, a famous poet and playwright, used this common phrase in the play Julius Caesar:

“He fell down in the market-place, and foamed at mouth, and was speechless.”

Example Sentence

  • The guy down the street is foaming at the mouth; he’s tossing things around in a fit of anger.
  • I try not to foam at the mouth when others upset me, but keeping calm is not always easy.

Similar Example:

  • After losing a game of chess, Nathan was seeing red and knocked over the board out of frustration.
  • He was up in arms after seeing the check from the restaurant; the cost of the food was excessive.

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