An endoscopy (looking inside) is used in medicine to look inside the body. The endoscopy procedure uses an endoscope to examine the interior of a hollow organ or cavity of the body. Unlike many other medical imaging techniques, endoscopes are inserted directly into the organ.

There are many types of endoscopes. Depending on the site in the body and type of procedure an endoscopy may be performed either by a doctor or a surgeon. A patient may be fully conscious or anaesthetised during the procedure. Most often the term endoscopy is used to refer to an examination of the upper part of the gastrointestinal tract, known as an esophagogastroduodenoscopy.