Butterflies in the stomach is a phenomenon characterized by the physical sensation of a "fluttery" feeling in the stomach. This sensation can be a physical sensation related to the body's fight or flight response or it can be an ineffable experience related to the psychology of love or nervousness and excitement.
Some believe that this is caused by the release of adrenaline when one is nervous, which pulls blood away from the stomach and sends it to the muscles. This reduced blood flow, in turn, causes the stomach to temporarily shut down, and is possibly the reason for reduced appetite during love sickness.
Butterflies in the stomach is most often experienced prior to important events, related to nervousness and can be experienced in situations of impending danger.
It is common for one to feel butterflies in the stomach when in the early stages of a relationship. It can be caused by nervousness and fear of the unknown. Butterflies in the stomach are often seen as a positive and harmless sign of subconscious feelings for romantic interest and are caused by the release of mood-altering endorphins. They are especially frequent in teenage romances. Many adults who have experienced multiple relationships themselves tend to experience this feeling more frequently at the time of an important life event. Sometimes just sitting back, relaxing and taking deep breaths can help to relieve the feeling.