Gastroscopy is the main investigative tool in the diagnosis of peptic ulcers in Thailand. In spite of its potential diagnostic value, endoscopic biopsy for histologic diagnosis is reserved only for suspected malignant gastric ulcers. Regarding treatment, duodenal ulcers can be treated satisfactorily with either low-dose antacid or one of the various H2-blockers, while gastric ulcers show a fairly good healing response to site-protective agents. Further trials using potent acid inhibitors, antibiotics against helicobacter pylori and plaunotol are being investigated.