An ENDOSCOPE for viewing the interior of the STOMACH. Introduced via the mouth and OESOPHAGUS, the long flexible instrument (also called an oesophagogastroduodenoscope) transmits an image through a fibreoptic bundle or by a small video camera. The operator can see and photograph all areas of the stomach and also take biopsy specimens when required. (See also FIBREOPTIC ENDOSCOPY.)