Causes of Bleeding From the Rectum

Pooping blood or finding blood in the stool is never normal

Seeing blood in the toilet bowl, in your stool, or on toilet paper can be quite startling. Bleeding in the colon (the large intestine) is not a symptom that should be ignored because it is never considered "normal." After the initial shock of having blood in your stool wears off, it's important to determine what is causing the bleeding.

If you have other symptoms in conjunction with the rectal bleeding, the cause might seem obvious, but that doesn't mean you should go it alone. Blood in the stool should always be discussed with a physician, even if it has happened before, or if you've previously been diagnosed with any of the conditions listed below. In the meantime, while you're waiting for that doctor appointment, find out more about some of the common conditions that could cause visible bleeding from the rectum.

Hemorrhoids

Hemorrhoids
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One very common cause of bleeding from the rectum is hemorrhoids. Hemorrhoids are actually veins in the rectum that have become swollen. They may cause pain, itching, and bright red blood on the stool or on the toilet paper, although many do not cause any symptoms at all. Hemorrhoids are typically not serious and can be treated at home. They should be investigated by a physician in the case that they are causing a large amount of bleeding or if they aren't getting any better after being treated.

Remember, when there is visible blood in the toilet, coating the stool or on the toilet paper, it should be investigated by a doctor. This is because there is a possibility of losing so much blood that the situation becomes dangerous, or that the bleeding is not from hemorrhoids at all, but from a more serious condition like inflammatory bowel disease (IBD) or colon cancer.

Diverticular Disease (Diverticulitis)

Diverticulitis in the descending colon region of the human intestine.
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Diverticular disease is quite common; as many as half of all people over age 60 have signs of diverticular disease. Diverticulosis is the presence of weak spots on the wall of the large intestine that develop into pockets or outpouchings. These outpouchings are called diverticula (a singular outpouch is called a diverticulum), and they generally don't produce any symptoms at all. People with diverticular disease might not know diverticula are there unless one or more of them get infected, which is then a condition called diverticulitis.

Diverticulitis might make a person seriously sick and could also cause abdominal pain. In some cases, the diverticula might bleed. The blood could be found in or on the stool, or bleeding could happen even without a bowel movement. Diverticular disease could cause quite a bit of bleeding and might or might not need treatment, but people with this condition should always see a physician if there is bleeding, even if it has happened before.

Anal Fissures

Cross section illustration of human anal column showing external and internal sphincters, and blood supply
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An anal fissure could be a complication of Crohn's disease or of childbirth, or it could be caused by hemorrhoids that have ulcerated or straining from severe constipation. An anal fissure is a tear in the anal canal and could cause bright red blood in the stool or on the toilet paper. Fissures also may cause pain during bowel movements, which sometimes is severe. Most fissures are classified as acute and will respond to non-invasive therapies that can be done at home. In many cases, the fissure won't come back, especially when care is taken to ensure that stools are kept soft and easy to pass (in other words, not too hard or too loose). A fissure that becomes chronic and is resistant to heal is not common but may need more intensive treatment, such as surgery.

Polyps and Colon Cancer

Polyp removal, artwork
SEBASTIAN KAULITZKI / Getty Images

One uncommon source of bleeding from the rectum is colon cancer. Colon cancer starts with polyps—outcroppings on the inside wall of the colon. Bleeding from colon polyps might not be enough to be visible to the naked eye, and most polyps don't bleed at all. Therefore, polyps could be growing in the colon without causing any signs or symptoms. Bleeding is a sign of colon cancer, but it might not appear until the cancer is in a more advanced stage. When polyps are removed during a colonoscopy, there is no chance of them developing into cancer. Screening for colon cancer with a colonoscopy, especially for those over the age of 50, is an important tool to remove polyps and prevent colon cancer.

Inflammatory Bowel Disease (IBD)

Intestine In Crohn's Disease
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Rectal bleeding due to IBD is more common with ulcerative colitis than it is with Crohn's disease. Bleeding tends to be a hallmark sign of ulcerative colitis because, in this form of IBD, the inflammation begins at the end of the colon in the rectum. Inflammation from Crohn's disease in the colon, particularly when it's located in the rectum, could also lead to visible blood on or in the stool. The blood coming from the ulceration in the colon that is caused by these diseases is often fresh, so it tends to be a brighter red in color. In the case of ulcerative colitis, there might be bowel movements that are mainly just blood. Blood from higher up in the digestive tract tends to be darker in color and might not be as visible in the stool.​

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