Endoscopy is a procedure in which a specially trained physician threads an instrument called an endoscope through an opening of the body in order to see inside of a hollow organ or body cavity such as the esophagus, stomach, lungs, intestine or bladder. (An “upper endoscopy” is when the test focuses on the upper digestive system and may also be referred to as an esophago-gastroduodenoscopy.) The scope is a very thin, flexible tube with a small camera at the end that can take pictures that are projected on a video monitor. Endoscopies are often performed as outpatient procedures within the doctor’s office, but may also be performed with the patient under full sedation at the hospital. Your physician may request an endoscopy to help determine why you are having certain unexplained gastrointestinal symptoms such as bleeding, pain, or swallowing difficulties. An endoscopy may also be ordered for purposes of collecting a biopsy or providing certain treatments such as esophageal dilation, removal of a foreign object or polyp, or stopping a GI bleed.