The purpose of this study was to investigate whether sublingual glyceryl trinitrate influences the size of the proximal stomach and postprandial symptoms in patients with functional dyspepsia. Twenty patients with functional dyspepsia were included in a double-blind, placebo-controlled crossover study with sublingual glyceryl trinitrate. All patients were scanned twice on consecutive days, receiving either placebo or 0.5 mg glyceryl trinitrate randomly 5 min prior to ingestion of 500 ml meat soup. Total symptoms, pain, nausea, and bloating were scored on a visual analog scale before and after the meal. Standardized ultrasonograms were obtained 1, 10, and 20 min postprandially of the proximal and distal stomach. The proximal stomach was larger in the sagittal section at 1 min postcibally (26.5 +/- 3.9 vs 24.8 +/- 4.9 cm2, P = 0.036) and 10 min postprandially (22.0 +/- 5.1 vs 19.8 +/- 5.3 cm2, P = 0.009) after administration of glyceryl trinitrate compared with placebo, whereas a tendency was observed after 20 min (18.7 +/- 5.5 vs 17.3 +/- 5.7 cm2, P = 0.076). The corresponding changes in the frontal diameters were 8.3 +/- 1.1 vs 7.8 +/- 1.2 cm (P = 0.067) after 1 min, 7.2 +/- 0.9 vs 6.4 +/- 0.8 cm (P = 0.001) after 10 min, and 6.3 +/- 1.1 vs 5.6 +/- 1.2 cm (P = 0.016) after 20 min. The area of the distal stomach was not different (P > 0.31) in the two groups. After administration of glyceryl trinitrate, the patients reported less pain (P = 0.048) and nausea (P = 0.023) 5 min postprandially, but this effect was reduced 15 min later. Total symptom score was improved by glyceryl trinitrate treatment (P < 0.042). Sublingual glyceryl trinitrate improves accommodation of the proximal stomach to a meal and reduces postprandial symptoms in a group of patients with functional dyspepsia.