Functional dyspepsia - Symptoms and causes - Mayo Clinic Overview Functional dyspepsia is a term used to describe a lingering upset stomach that has no obvious cause Functional dyspepsia (dis-PEP-see-uh) also is called nonulcer dyspepsia Functional dyspepsia is common It is a constant condition, but symptoms don't happen all the time Symptoms are like those of an ulcer They include pain or discomfort in the upper belly, bloating, belching and