Causes In healthy individuals, the interdigestive phase is characterized by a characteristic migratory complex motion wave (MMC), in which MMC phase III plays an important role as a scavenger, and the postprandial phase enters the digestive phase, in which the proximal stomach is adaptively dilated to accommodate food, and the distal stomach is contracted and peristaltic to digest food and turn it into fine particles, and the coordinated motion of the gastric sinus, pylorus and duodenum plays an important role in the emptying process. In patients with functional dyspepsia, abnormal sinus, pylorus and duodenal motility is not only present in the digestive phase but also in the interdigestive phase, the latter including reduced frequency of MMC III, reduced motility of MMC II and duodenogastric reflux, etc. As a result, patients have symptoms on an empty stomach, and they do not decrease or even increase after meals. The etiology and pathogenesis of functional dyspepsia are still not fully understood and may be related to a variety of factors. It is currently believed that upper gastrointestinal tract dysfunction is the main pathophysiological basis, and psychological factors and stress factors have been considered to be closely related to its development.