 For removal of large flat lesions of the gastro-intestinal tract injection of a solution under the lesion creates a safety cushion and protects from damage to the gastrointestinal tract wall. Various solutions are currently used, but some of them are easy to inject but quickly dissipate normal saline,other solutions are more longer lasting hydroxypropyl methylcellulose, hyaluronic acid, etc but are very difficult to inject and can be expensive and not always available. The investigators performed previously animal experiments which demonstrated that blood is easy to inject and creates a protective cushion which lasts longer than other fluids which are currently used for protective cushion creation. 