Melanosis coli Wikipedia Pigmented Lesions of the Oral Mucosa Pocket Dentistry ORAL MELANOTIC MACULE (OMM) (Also called focal melanosis labial melanotic macule) A benign, localized, flat pigmented lesion of the oral mucosa Caused by a focal increase in melanin production Intramucosal melanocytic nevi CCIDE Dove Medical Press What Caused These Multiple Hyperpigmented Macules of the Mouth? 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