Endoscopy in general sense means intrusion into and examination of the inner body cavity by using a device equipped with a special camera. Examination of upper digestive system, that is, esophagus, stomach, and duodenum is called as “esophagogastroduodenoscopy, while the examination of digestive system, that is, large intestine and the distal part of small intestine is called as “colonoscopy”. Usually 6-8 hours of fasting is sufficient prior to upper digestive system examination, while a one-day special diet and cathartic drugs are required prior to lower digestive system examination. Endoscopy procedure can be performed anesthetically with accompaniment of an anesthetist; however, it can also be completed with local anesthesia by experienced endoscopists within a short time without causing pain.