Main symptoms: epigastric discomfort, abdominal distension, abdominal pain, heartburn, nausea, vomiting, etc. Mechanism: 1, direct stimulation of the esophagus, stomach and duodenum, destruction of the mucosal barrier. 2. Inhibit the synthesis of prostaglandins, resulting in extensive damage to the gastric and duodenal mucosa (erosion or ulceration) causing bleeding.