You could experience a hypersensitive gag reflex for several reasons, according to the National Library of Medicine. Sometimes the gag reflex is triggered by something physical, such as the sticky texture of bananas. Anxiety could trigger the gag reflex, which could partially explain why some people will experience a hypersensitive gag reflex even before a dentist touches their mouths. Your gag reflex could also kick in when you see or smell something off-putting (via Medical News Today).
A hypersensitive gag reflex could stem from some food trauma during childhood, such as a time when you choked on some type or texture of food (via NBC News). You could also experience this hypersensitivity if you weren’t introduced to solid foods until after you were 7 months old. While your body can’t tolerate solid foods before you’re 4 months old, your gag reflex will gradually relax when you’re 4 to 6 months old as more solid foods are introduced. Lastly, a hypersensitive gag reflex could also be inherited from your parents.