From the Research
Melanosis coli is a harmless condition that does not require specific treatment, and patients can be reassured that it does not increase cancer risk or cause symptoms. The condition is typically caused by long-term use of anthracene laxatives such as senna, cascara, and aloe, as supported by a study published in 2022 1. If present, the pigmentation will gradually fade over 6-12 months after discontinuing the causative laxatives. For patients using these laxatives regularly, I recommend switching to alternative constipation treatments such as:
- Increased dietary fiber (25-30g daily)
- Adequate hydration (at least 8 glasses of water daily)
- Regular physical activity
- Non-anthracene laxatives like polyethylene glycol (Miralax, 17g daily) or psyllium (Metamucil, 1 tablespoon 1-3 times daily) The dark coloration occurs because anthracene compounds damage colonic epithelial cells, which are then engulfed by macrophages that accumulate in the lamina propria of the colon, as described in a study published in 2015 2. These macrophages contain lipofuscin pigment, giving the characteristic dark appearance seen during colonoscopy. A comprehensive review published in 2020 3 also supports the idea that melanosis coli is a reversible condition that can be managed by changing living habits and bowel function. Additionally, a study published in 2004 4 reported a rare case of melanosis coli involving pericolonic lymph nodes, but this is not a common finding and does not change the overall management of the condition. Overall, the most important step in managing melanosis coli is to address the underlying constipation with safer alternatives, as supported by the most recent and highest quality study available 1.