A virus like Norwalk attacks the small intestine and causes a condition called gastroenteritis (spelling?) or inflammation of the stomach lining. If your stomach lining is inflammed, naturally it cannot tolerate being in use (holding food). In my opinion, v* would seem to be the body's attempt to relieve itself of the pain. Everything I've heard agrees with the idea that v* does not expell the virus or shorten the duration. It is a natural reaction to the virus but not a necessary part of recovery. Many people don't v* with Norwalk or v* only once and they still recover.