How did butterflies get in your stomach? Well, those really aren't butterflies in there. "Butterflies in the stomach" is a way of describing those nervous, fluttery feelings you might get before a test or an important game. An imaginative writer created the phrase to describe the feeling, and people have been using it ever since.
These tummy flutters are normal and happen to many people — even grown-ups. Some people believe having a few butterflies might even help you perform better by keeping you on your toes.