Examination of the interior of a canal or hollow viscus my means of a special telescope- usually used in reference to an EGD (esophago-gastro duodenoscopy) where the doctor performs an endoscopic exam of the esophagus, stomach and first portion of the intestines. Endoscopy is a procedure in which an endoscope – a flexible lighted tube – is used to inspect body organs and cavities. Endoscopes are inserted through natural openings in the body such as the mouth and the anus. Types of endoscopy include colonoscopy, sigmoidoscopy, gastroscopy, enteroscopy, etc. Endoscopy facilitates minimally invasive surgery. Risks associated with endoscopy include infection, perforation, allergy to the contrast dyes, and over-sedation.