Gastrointestinal endoscopy has experienced tremendous developments in technology and equipment over the past decades. It is not only a diagnostic tool, but it also allows some interventional treatments in benign and malignant digestive diseases. Operative colonoscopy has been used to perform curative treatment of various kinds of polyps, flat and carpet-like adenomas and early colorectal carcinomas. Endoscopic palliative treatment strategies, such as the placement of self-expandable metal stents (SEMS), laser ablation, photodynamic therapy (PDT), argon plasma coagulation (APC), electrocoagulation, and injection therapy, have been proved to effectively alleviate advanced colorectal cancer (CRC) associated symptoms and maintain or improve the quality of the patient's remaining life.