The endoscope enables us to look down into the oesophagus and stomach as well as into the trachea and inside the bronchi of the lungs. Using the endoscope we can take biopsies, which are small samples of tissue, from the lining of the trachea, oesophagus and stomach. At the other end of the patient, the endoscope can also be used to look into and take biopsies of the colon. The patient needs to be under general anaesthetic for endoscopy.