Endoscopy comes in a variety of forms. Esophagogastroduodenoscopy (EGD), also known as upper endoscopy, gastroscopy, enteroscopy, endoscopic ultrasonography (EUS), endoscopic retrograde cholangiopancreatography (ERCP), colonoscopy, and sigmoidoscopy are some of the procedures that use natural bodily apertures. Natural orifice surgery (NS) is a new surgical technique that uses small instruments such as cameras mounted on flexible tubes to view and treat tissues within the body. These techniques are useful in diagnosing and treating conditions not readily accessible by traditional methods. In addition to these diagnostic tools, therapeutic endoscopes are used to perform procedures during endoscopy. Endoscopes can be rigid or flexible. Some examples of rigid endoscopes include bronchoscopes, duodenoscopes, gastrostomy tubes, nasogastric tubes, and spinal needles. Flexible endoscopes include colonscopes, esophagoscopes, gingivitis probes, nasal aspirators, and suction catheters. Endoscopy allows physicians to see inside the body without cutting open tissue. This method provides information about organs such as the stomach, intestines, lungs, and liver that other imaging tests cannot. Endoscopies are useful for diagnosing disease, locating abnormalities, removing polyps, and performing other tasks. In addition, they can show how certain diseases progress over time.