<p>The diagnosis of functional disorders of the upper gastrointestinal tract relies on clinical evaluation after exclusion of most frequent organic diseases. Diagnostic techniques contribute to better characterization of disease, choice of specific therapy, and follow-up. Functional ultrasonography was introduced in the early ‘80&#xa0;s for the non-invasive study of gastric and gallbladder emptying without ionizing radiation, during fasting and postprandially. This technique detects dysfunctional motility in several gastrointestinal and systemic conditions, and can be used along with the assessment of real-time satiety and gastrointestinal symptoms after food ingestion, and dosing of hormones involved in the modulation of gastrointestinal and metabolic homeostasis. Functional ultrasonography has been increasingly used to explore the gastrointestinal pathophysiology, the gut–brain interaction, the effects of drugs (such as antidiabetics), the response to specific dietary and feeding patterns, and to support the development of nutraceuticals. In this evolving scenario, ultrasonography stands as a widely available, highly sustainable, non-invasive, repeatable, safe and low-cost tool, as compared with more expensive, less sustainable or still scarcely standardized procedures to study gastric and gallbladder motility as scintigraphy, wireless motility capsule tests, ¹³C breath tests, or magnetic resonance imaging. Functional ultrasonography not only provides reliable data in experimental protocols, but also in the assessment of clinical conditions as dyspeptic symptoms, diabetes, gastroenteric and neurological diseases, critical illness, and as a benchmark to evaluate the gastrointestinal effects of innovative drugs.</p>