Oesophago-gastro-duodenoscopy (gastroscopy for short) enables a doctor to directly view the interiors of the upper gastrointestinal tract. Thin and flexible optical instrument (gastroscope) is introduced through the mouth. First, oesophagus is examined and then follows the inspection of stomach and duodenum. Endoscopic examination of the upper digestive system is by far more accurate than a contrast X-ray examination. Gastroscopy will be conducted by a qualified doctor, specialist gastroenterologist.