Pressure activity in the stomach and upper intestine was studied in 104 patients referred to the Mayo Clinic for evaluation of functional symptoms (nausea, vomiting, upper abdominal pain, or other dyspeptic symptoms in the absence of structural gut abnormalities). Manometric abnormalities were found in 75 patients. Forty-three of these had gastric abnormalities and 32 patients had both gastric and intestinal abnormalities. In the stomach, decreased antral phasic pressure activity after a solid meal was the most common abnormality. In the upper intestine, unpropagated bursts of phasic and tonic contractile activity were a relatively frequent abnormality but a number of other altered manometric patterns also were observed. Digestive tract symptoms were not good predictors of the presence or site of the gastrointestinal manometric abnormalities. Patients with associated neurologic, urologic, or metabolic (diabetes) disease were more likely to exhibit manometric abnormalities than were those without evidence of disease outside the gut. Almost two-thirds of the patients with symptoms and normal manometry presented features suggestive of psychiatric disease. We conclude that in patients with severe functional-type symptoms gastrointestinal manometry is a useful technique to evidence the underlying gut motor disturbance that is present in a relatively high proportion of these patients.