Related Experiment Video
Updated: Aug 12, 2026

Flexible Colonoscopy in Mice to Evaluate the Severity of Colitis and Colorectal Tumors Using a Validated Endoscopic Scoring System
Published on: October 17, 2013
Melanosis of the rectum in patients with chronic constipation
Abstract:
In patients with constipation the prevalence of melanosis in rectal biopsies was evaluated in an attempt to correlate its occurrence with laxative consumption and intestinal stasis. Melanosis was present in 58 percent of the patients and in none of a control group. Melanosis was present in 73.4 percent of patients consuming anthracene laxatives and in 26.6 percent of those not consuming anthracene laxatives (P less than 0.01). No correlation was found between the occurrence (and grading) of melanosis and pattern of transit through the large bowel, bowel movements, and duration of symptoms. Results of this study seem to indicate that intestinal stasis is not a cause of melanosis of the colon and rectum and confirm that melanosis may well be due only to the consumption of anthracene laxatives; melanosis coli does not appear to be a sensitive marker of impairment of motor function in the "cathartic colon."
Related Concept Videos
Pigmentation
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
Skin Cancer
Basal Cell Carcinoma (BCC): BCC is the most common type of skin cancer, accounting for about 80% of cases. It typically develops in...
Chronic Bowel Disorders: Introduction
Irritable Bowel Syndrome (IBS) is a common disorder affecting the gastrointestinal tract. The distinctive feature is recurrent abdominal pain associated with altered bowel movements, manifesting as constipation, diarrhea, or fluctuating between both. The...
Drugs for Treatment of Constipation-Predominant IBS
Assessment of the Rectum and Anus
Rectal Inspection
Begin by inspecting the perianal and anal areas for color, texture, rashes,...
Diverticular Disease of the Colon

