Background: In view of the popular acceptance of the adenoma-carcinoma sequence, endoscopic polypectomy is indicated for the removal of colorectal adenomas. Larger or sessile lesions should be removed by an experienced endoscopist, but complications such as hemorrhage and perforation still may occur. Methods: To render the removal of sessile lesions feasible by endoscopic polypectomy and to reduce the risk of complications, we attempted local submucosal injection of hypertonic saline-epinephrine solution [(HSE) a mixture of 4.7% sodium chloride and 0.005% epinephrine] before electrosurgical snare excision; 0.5-2 ml HSE were injected into the base and immediate vicinity of polyps to produce mucosal bulging. Results: Between August 1990 and April 1992, 645 polyps in 403 patients were removed by this method; sessile lesions could be more readily removed. Of these, 17 (2.6%) revealed invasive carcinoma and 19 (3.0%) carcinoma in situ. The largest sessile polyp removed was 40 mm in diameter and 7 mm in height and contained a carcinoma in situ. Even a 6-mm depressed adenoma and two rectal carcinoid tumors could be excised completely. No serious complications were encountered with this method. Conclusion: We conclude that local injection of HSE makes the endoscopic removal of colorectal polyps much easier and safer.