Melanosis Coli

What is melanosis coli?

Melanosis coli is a benign (noncancerous) condition that causes the inner lining of your colon to be a darker color than usual. It typically makes parts of your colon appear dark brown or black. The condition itself doesn’t cause any symptoms. Instead, a healthcare provider may notice the discoloration during an imaging procedure.

Learning your colon is an unusual color may feel alarming, but it’s not a sign you’re sick or have developed a serious condition. The dark color is from a pigment found in your colon wall called lipofuscin. It can build up if you’re taking certain types of stimulant laxatives for too long. Stimulant laxatives cause the nerves in your gut to contract, so you can have a bowel movement (poop).

Still, your provider will advise you to stop taking the laxatives causing melanosis coli once they diagnose the condition. Once you stop, your colon will return to its normal color.

Is melanosis coli serious?

Melanosis coli isn’t serious, and it doesn’t increase your risk of developing a serious condition.

What are the symptoms of melanosis coli?

Melanosis coli doesn’t cause symptoms. Most people learn they have melanosis coli because it shows up during an unrelated imaging procedure, like a colonoscopy or a flexible sigmoidoscopy.

During a colonoscopy, a gastroenterologist uses a scope to look inside your colon and check for growths (like polyps) or signs of colon cancer. A flexible sigmoidoscopy is a similar procedure, but the scope only checks the lower third of your colon.

What causes melanosis coli?

Melanosis coli usually occurs in people who use certain laxatives for too long. Laxatives can help you have a bowel movement if you’re struggling with constipation, but they’re designed only to provide relief in the short term. They’re not a long-term solution to chronic constipation.

The laxatives associated with melanosis coli contain an organic compound called anthraquinones, found in some plants. While they can provide constipation relief, you shouldn’t take them for longer than two weeks.

Researchers suggest that using these laxatives for too long, typically longer than two weeks, can damage the cells lining your colon. When those cells are damaged, they release the lipofuscin pigment. This benign release and accumulation of lipofuscin can cause the lining to appear dark brown or black. Luckily, when this happens, your colon lining repairs itself quickly and efficiently.

Laxatives containing anthraquinones include:

• Aloe.
• Buckthorn.
• Cascara sagrada.
• Frangula.
• Rhubarb.
• Senna.

Causes other than laxative use

Less commonly, people develop melanosis coli without previous or ongoing laxative use. Other potential causes include:

• Chronic diarrhea.
• Inflammatory bowel disease (IBD).
• Irritable bowel syndrome (IBS).
• Vitamin E deficiency.
• Using nonsteroidal anti-inflammatory drugs (NSAIDs).
• Using anthralin (a cream to treat a skin condition called psoriasis).
• Consuming foods high in unsaturated fatty acids (usually plant-based foods).

How is melanosis coli diagnosed?

Melanosis coli is usually an incidental finding during an endoscopy procedure, like a colonoscopy. These procedures allow your provider to see inside your colon to check for growths, like polyps or colon cancer. Your provider may perform a colonoscopy or flexible sigmoidoscopy to investigate what’s causing your constipation — a common condition associated with melanosis coli.

While healthcare providers aren’t specifically looking for melanosis coli, they may notice the discoloration during the procedure.

How is melanosis coli treated?

Since most cases involve laxative overuse, the most common treatment involves stopping taking laxatives containing anthraquinones. Melanosis coli is a reversible condition, so your colon lining will return to its typical color once you stop the laxatives. It can typically take six to 12 months for melanosis coli to disappear after you stop taking the laxatives.

In the meantime, there are remedies you can use to manage constipation.

• Increase your fiber intake. Eat more high-fiber foods, like whole wheat pasta, whole grain breads, fruits and veggies.
• Stay hydrated. Your body needs plenty of water to soften your poop and keep your bowel moving. Be sure you’re drinking enough hydrating fluids daily. Avoid drinks that can dehydrate you, like drinks containing alcohol or caffeine.
• Get active. Exercise can stimulate bowel movements, allowing you to poop.
• Switch laxatives. You may need to switch from a stimulant laxative to another type, like a bulking laxative or a stool softener. Your healthcare provider can advise you on which types work best for you.

If these solutions don’t help, your healthcare provider can work with you to find a treatment that does.

Can melanosis coli be prevented?

The best way to avoid melanosis coli is by avoiding laxatives with anthraquinones. Follow your provider’s advice on how to manage (and prevent) constipation.

What can I expect if I have this condition?

Your colon should return to its normal color once you stop taking laxatives with anthraquinones or treat the underlying cause. The discoloration won’t affect your colon or overall health in any way.

Is melanosis coli cancerous?

No, it’s not. Melanosis coli is not a sign of colon cancer. It’s also not a sign of a condition that means you’re at increased risk of colon cancer. Instead, it’s a harmless discoloration of your colon lining.

Some people worry about the cancer link because of the medical history of anthraquinone laxatives. Studies that tested the safety and effectiveness of these drugs showed that long-term use can cause tumors to form in rats. But there’s no evidence that these same drugs cause similar growths in humans. Researchers continue to test these drugs for safety, especially when it comes to long-term use for treating constipation. To date, there’s been no evidence of a direct link between anthraquinone laxative use and colon cancer (or any other type of cancer).

Still, overusing any laxative (including stimulant laxatives) can pose health risks. Work with your healthcare provider to find a treatment plan that’s both effective and safe.

A note from Cleveland Clinic

Many people imagine darkened tissue as a sign of tissue death — something serious. But with melanosis coli, the dark tissue isn’t an indication of disease or irreparable damage. Usually, it’s a sign to take a different approach to how you’re managing constipation. Talk to your healthcare provider about long-term approaches to managing and preventing constipation so that you’re not relying on laxatives with anthraquinones.