Seeing blood with your stools is just plain frightening, as this immediately brings to mind colon cancer.

Though hemorrhoids are a common cause of blood mixed with poop, it’s hard to ignore more sinister explanations.

If you’ve ever read a symptom list for colon cancer, one of the bullet points was surely something like “bloody stools” or “blood mixed with stools.”

But just how common does this happen, especially since an intestinal ulcer and Crohn’s disease, as well, can cause blood in one’s feces?

“Colon cancer generally does not cause overt bleeding unless the tumor arises is the distal (closer to the rectum) part of the colon,” says Andrew Black, MD, Diplomate of the American Board of Internal Medicine & Gastroenterology who’s based in Norman, OK.

Black, Maroon and Red

“Dark/black stools generally reflect bleeding from the stomach, small intestine or the beginning of the colon.

“Maroon stools are more likely to reflect bleeding from the left side of the colon.

“Bright red blood is typically from the sigmoid and/or rectum. Bright red blood is generally the most common and innocuous [meaning, more likely to have a benign cause].

“The other two are still fairly common and generally indicate more serious causes of bleeding.”

As far as how often, or what percentage of cases, colon cancer presents with noticeable blood in the stool, Dr. Black says, “I don’t think I can quote statistics.

“However, I would imagine that most people at some point or another (nearly 100%) experience bright red blood either mixed in or with bowel movements and/or on the toilet paper,” from causes OTHER than colon cancer.

“Black stools (melena) are much less common,” overall, but are more likely to come with colon cancer than is red, fresh-looking blood.

Other symptoms of colon cancer besides blood mixed with feces: unexplained weight loss, unexplained fatigue, loss of appetite, pencil thin or ribbon-like stools, feeling a need to void even after bowel movements, and constipation alternating with diarrhea.

Dr. Black has presented many GI-related research papers at national conferences. He is an active member of Norman Regional Hospital, and West Norman Endoscopy Center.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer. 


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