Transcutaneous ultrasonography (US) is an excellent modality not only in imaging the gastrointestinal tract (GIT) but in evaluating its functions as well by observing peristalsis and the quantity and quality of intestinal contents. The normal wall structures in US are depicted as three layers. The first part of the GIT, the cervical esophagus, is well delineable behind the left lobe of the thyroid gland (rare behind the right lobe). The esophageal mid-portion is covered and not accessible to US, whereas the terminal esophagus and the cardia can be defined in almost every individual. In patients with dysphagia, routine US examination should focus on this area, looking for the general features of GIT pathology: asymmetric wall thickening with partial or complete loss of the layered structures (“pathological cocarde”) mostly rule echopoor, with a loss of peristaltic movements, and a prestenotic dilatation and pathologically enhanced fluid contents. These pathologies mean in the stomach a sometimes considerable wall thickening, due to malignancies of various origins (which of course cannot be differentiated by means of US). Once they form an obstacle, a gastric retention will follow, or other clinical signs will prompt diagnostic efforts. The duodenum as the first part of the small intestine, hardly delineable in normal conditions, is often involved in pancreatitis with an overall swelling of its wall structures with good visibility. This holds true in other diffuse inflammatory reactions of the small intestine as well as e.g., in gluten sensitive enteropathy or in less a degree in severe infectious enteritis. Subileus or ileus will be detected by US earlier than by X-ray diagnostics, since US is not depending from separating gas formations, dilatation and pathological peristalsis are directly and repeatedly easily demonstrated by US. Finding the obstacle, for example in Crohn‘s disease, needs a more detailed examination but it is as a rule possible to find the site of the intestinal blockade (be it by compression or by luminal obstruction) and to either define the true nature of the blockage or to give at least a good differential diagnostic approach to the most probable reason(s). Ileocecal junction and the valve are as a rule not visible in healthy individuals. In augmented intestinal liquid filling, however, they can be defined easily including their possible pathology. Appendicitis, still sometimes a really difficult clinical diagnosis, can be defined in the classic cases without a problem, confirming the clinical findings and quickening the indication for operation. Colon pathology, both in inflammatory and in tumorous processes, is an ideal target for clinical ultrasonography as well, predicting quite often the endoscopic findings. Hydrocolonosonography is another early variant of virtual colonoscopy, a merely considered but true fact with the drawback of too low an economic challenge or promise. In conclusion, intestinal US, starting with the esophagus and ending with the rectum, is an ideal noninvasive diagnostic approach in GIT disease, and an optimum partner for endoscopical intestinal diagnosis.