Do you remember a time when you experienced butterflies in your stomach? I had a crazy bout of butterflies just today, thanks to my new research project! But this is completely normal, and we all experience it at some time or other. Butterflies are usually associated with a strong emotion (anxiety, nervousness, or even love) and can be so strong that they leave us feeling nauseated. Despite not always being a welcoming experience, this common sensation is caused by our gut-brain connection.