Melanosis Coli

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After completing a thorough lab analysis of your recent colon biopsy, a specialized doctor called a pathologist reported a diagnosis of melanosis coli, an abnormal discoloration of the lining of the colon. Melanosis coli is not cancer and does not appear to increase the risk of developing colorectal cancer.

About the Condition

The colon, or large intestine, is a tube lined with muscles that extracts moisture and nutrients from food, storing the waste matter until it is expelled from the body. It is typically 5–6 feet long in adults. The last segment of the colon is called the rectum.

Melanosis coli occurs when the normally pink-colored lining of the colon turns dark brown or black from an accumulation of pigment in its connective tissue layer. The condition is often discovered during a routine colorectal cancer screening exam using a camera (endoscope) inserted through the anus.

The principal cause of melanosis coli is the ongoing use of stimulant laxatives to treat constipation. Such laxatives are only intended for occasional use.

Melanosis coli does not generally cause any symptoms; however, some health concerns may arise from the condition, most notably laxative dependence.

The abuse of laxatives can result in the degeneration of intestinal nerves and dulling of natural bodily responses that stimulate bowel movements. When this happens, the colon instead relies on the laxatives to bring on bowel movements.

In addition, the ongoing use of laxatives may cause a potassium imbalance in the body, which in rare cases can become a serious health threat.

Treatment Options

No medical treatment is necessary for melanosis coli. Patients are advised to stop taking laxatives, which usually reverses the discoloration of the colon after a fairly short period of time.

If constipation — generally defined as the passage of small, hard and dry bowel movements fewer than three times a week — is an ongoing problem, your doctor may suggest that you take fiber supplements, which are safe for long-term use. Be sure to talk with your doctor about what choices are best for your individual situation.

What You Can Do

You can reduce the occurrence of constipation by addressing the key factors that contribute to the condition: low fiber and water intake and a sedentary lifestyle.

Be sure to eat a low-fat diet high in fruits, vegetables and whole grains and to drink about two quarts of fluids (mostly water) each day. Also, take part in some form of regular exercise, especially activities that engage the abdominal muscles (e.g., walking on an uneven path rather than a flat, even surface). In addition, you should not ignore the urge to have a bowel movement.

Other steps you can take to maximize your health and reduce the risk of developing colorectal and other types of cancer include:

•  Avoiding the use of tobacco
•  Limiting consumption of alcohol and red meat
•  Maintaining a healthy body weight
•  Getting enough sleep every night
•  Visiting your doctor regularly and promptly reporting any new symptoms

Additional Resources

American Cancer Society, 800.227.2345,
eCureMe, (323) 731-9200,
Digestive Diseases Information Clearinghouse, 800.891.5389,

This patient resource sheet is provided to you as a service of CBLPath® and is intended for information purposes only. It may not fully describe all aspects of your diagnosis and is not meant to serve as medical advice or a substitute for professional medical care. Your physician can provide you with a thorough explanation of your diagnosis and appropriate treatment options, which may vary. Only you and your physician can determine your best treatment plan.

Updated 9.07