The etiology of upper digestive complaints in uremic patients, which frequently cause morbidity, is unclear. By means of ultrasonography we studied the emptying of the gastric antrum in 15 patients suffering from end-stage renal disease and in 15 controls. In addition, we tested for autonomic neuropathy in the chronic renal failure (CRF) patients using cardiovascular tests. The antral filling and emptying of a semisolid standardized test meal was assessed by measuring cross-sectional areas of the antrum along the plane of the mesenteric vein at regular intervals after a semisolid test meal. Postprandial antral cross-sectional areas were similar in controls and in the total of the renal failure patients. CRF patients without autonomic neuropathy (4/15) showed hastened antral emptying as evidenced by significantly diminished postcibal antral expansion. Only the CRF subgroup with symptoms of both parasympathetic plus sympathetic autonomic neuropathy (6/15) had delayed antral emptying compared to controls as assessed by planimetry of the area under the curve in postprandial antral cross-sectional areas. The CRF subgroup with exclusively parasympathetic neuropathy (5/15) had antral emptying similar to the controls. The symptom score as assessed by a standardized questionnaire of the CRF group with autonomic neuropathy (11/15) correlated significantly both with the fasting antral cross-sectional area and inversely with antral expansion immediately after finishing the test meal. Antral emptying showed a trend towards an inverse relationship to the symptom score, which reached statistical significance only in the CRF subgroup with sympathetic plus parasympathetic autonomic damage.(ABSTRACT TRUNCATED AT 250 WORDS)