Endoscopy may be used to investigate symptoms in the digestive system, including nausea, vomiting, abdominal pain, difficulty in swallowing and gastrointestinal bleeding. It is a simple procedure that allows a doctor to look inside a human body using an instrument called an endoscope. A cutting tool can be attached to the end of the endoscope, and the apparatus can then be used to perform minor procedures such a tissues biopsies, banding of oesophageal varices or removal of polyps.