Water emersion colonoscopy is a well-established alternative to conventional "air" colonoscopy and is in fact preferred by many endoscopists. Studies have shown that using water instead of air decreases the discomfort of colonoscopy, measured by the amount of sedative and pain medication used, time to complete the colonoscopy, and recovery time, and increases cecal intubation rates. Interventional Endoscopy Services (IES) at CPMC has taken the concepts of water emersion colonoscopy one step further in order to developed a novel method of "underwater" EMR. This technique was inspired by the observation that the muscularis propria of the colon retains its native thickness (1-2 mm) and circular configuration during underwater EUS examination. Furthermore, water immersion "floats" mucosal lesions away from the deeper wall layers, eliminating the need for a "safety cushion" created by submucosal injection. One drawback to the underwater technique is that in the case of poor preps, residual feces in the colon is suspended in the water, interfering with visualization. Additionally, the use of water often causes soiling of the gurney as a result of water seepage from the rectum during the procedure, which requires additional sanitary attention during the procedure.