Diagnostic agents, preparations and substances for medical and surgical purposes; Diagnostic agents, preparations and substances for medical purposes, namely, the enhancing of adenomatous, cancerous and other proliferative lesions in the colon for patients undergoing colonoscopy and for the visualization of colonic adenoma in patients undergoing screening colonoscopy including patients at high risk of colorectal carcinoma (CRC), including those with previous history of polyps at prior colonoscopy, patients with colorectal cancer and patients with family history; Diagnostic reagents and contrast media for medical and surgical use; Contrast media for use with imaging medical equipment; Contrast media for use with colonoscopic equipment; pharmaceutical preparations for use in gastroenterology; pharmaceutical preparations for use in colonoscopy; pharmaceutical preparations for the differentiation of the tissues of the intestines and colon and lesions thereto; pharmaceutical preparations for use in the colonoscopic diagnostic evaluation; methylene blue for pharmaceutical, medical, surgical and medical diagnostic purposes; dye for pharmaceutical, medical, surgical and medical diagnostic purposes