Benign Discoloration Poses Questions Endoscopic Imaging of Melanosis Coli Pigmentation (melanosis) of the colon Stock Image C009 6107 Science Photo Library Bring Awareness to Crohn's and Colitis in December AAPC Knowledge Center Melanosis coli is dark brown black pigmentation of colorectal mucosa associated with chronic use of laxatives containing anthraquinone. Examples of such laxatives include senna and rhubarb derivatives. Clinical Importance: There is no association MELANOSIS COLI** Melanosis coli is a disorder of pigmentation of the bowel wall. Histology demonstrates pigment laden macrophages It is associated with laxative abuse, especially **anthraquinone compounds such as senna**