define functional dyspepsia
Click here to download a pdf of this information. Image Credit: Â© bigstockphoto.com/Olezzo. Functional dyspepsia (FD) is a chronic disorder of sensation and movement (peristalsis) in the upper digestive tract. Peristalsis is the normal downward pumping and squeezing of the esophagus, stomach, and small intestine, which begins after swallowing. We call this disorder functional because there are no observable or measurable structural abnormalities found to explain persistent symptoms.