DEAR DOCTOR K: Whenever I'm stressed out my stomach clenches up in knots. Why does it do that?
DEAR READER: A particularly sad experience is described as "gut-wrenching." Hearing about a gruesome crime makes you "feel nauseated." An upcoming presentation gives you "butterflies in your stomach." We use these expressions because anger, anxiety, sadness, elation and other emotions can trigger symptoms in our gastrointestinal tract.