This expression means that you're really scared or anxious about something. The ancient Greek poet Homer used the phrase thousands of years ago when he wrote the famous poem The Iliad, and people have been using it ever since. When your heart starts pounding so much that you can feel a thumping in your throat, it may feel like you "have your heart in your mouth." But the good news is that your heart can't move into your throat, mouth, or anywhere else. It stays put! 

Reviewed by: Mary L. Gavin, MD
Date reviewed: February 2007