Colonoscopy, the most common examination and treatment method in anorectology. The main indications for colonoscopy are colitis, proctitis, rectal polyps, colon polyps, rectal tumors, colon tumors, and also giant colon, and it costs$360. With the addition of blood test and oral electrolyte dispersion, the general cost is about 500 yuan. Colonoscopy can not only check, but also treat. If inflammation is found, topical medication can be administered through colonoscopy, and its main role is still the treatment of colon polyps. If colon polyps or rectal polyps are <2cm in diameter, polypectomy can be performed under colonoscopy, including relatively shallow rectal and colon tumors, i.e. carcinoma in situ or called high-grade intraepithelial neoplasia, which can also be removed under colonoscopy. Its cost is usually around 10,000 RMB.