Rectal Bleeding – Causes of Blood from the Rectum

The sight of blood in the stool can understandably cause a person to become very worried. However, not all cases of blood in the stool are caused by serious problems. Blood in the stool can appear in different forms. The cause may either be internal bleeding or external bleeding. In some cases, the blood may not be visible to the naked eye, but can be detected with stool tests. Invisible blood in the stool is technically referred to as occult blood.

The color of any visible blood in the stool also indicates whether it is fresh blood or old blood. Old blood has a dark brown appearance. This type of blood may be present as specks or particles, rather than in a liquid form. On the other hand, fresh blood appears as a bright red fluid. It might be noticed during or immediately after a bowel movement when the water in the toilet bowl turns red.

In some cases, one may become aware of blood in the stool only upon wiping the anus with a tissue paper after finishing a bowel movement. This type of bleeding is most likely due to hemorrhoids or piles. Any type of blood in the stool should prompt a visit to the doctor.

Signs and Symptoms of Rectal Bleeding

One should take note of the following signs and symptoms when blood appears in the stool:

  • Blood in the stool – old blood has a dark brown or tarry appearance and is technically referred to as melena while fresh blood in the stool has a bright red color and is technically referred to as hematochezia.
  • Pain during or after a bloody bowel movement. The location, trigger, duration, and character of the pain should also be noted. In addition, factors that may provide relief from the pain may also be important to remember.
  • Mucus in the stool.
  • Abnormalities in consistency, color, and volume of the stool.

Read more on normal vs abnormal stool.

At times, blood in the stool may also be accompanied by nausea and vomiting. One should also pay attention to the presence of any blood in the vomit (technically referred to as hematemesis). If there is unexplained weight loss and persistent bleeding from the rectum, one should seek immediate medical attention. Even if there are no other accompanying signs and symptoms, persistent rectal bleeding and unintentional weight loss should be taken seriously.

Causes of Rectal Bleeding After a Bowel Movement

Rectal bleeding could occur due to many different reasons. Some of the causes can be serious. The following are some of the more likely causes of rectal bleeding during a bowel movement.


Hemorrhoids (also known as piles) refer to veins that get enlarged within the lower rectal and anal region. The enlargement of these veins is caused by inflammation. Hemorrhoids are one of the most frequent causes of fresh blood in the stools. Apart from rectal bleeding, the presence of hemorrhoids may also be indicated by an itchy anus and the presence of a sensitive palpable lump in the anus or the lower rectum.

Read more on hemorrhoids.

Anal fissures

Anal fissures refer to small tears within the anal mucosa. These tiny tears are mainly caused by long-term diarrhea and constipation. Passage of stools over these fissures makes defecation a painful affair. The tears may also be visible in the area around the anus. Apart from pain and bleeding, anal fissures may also be accompanied by an itchy anus.

Inflammatory bowel disease

Inflammatory bowel disease (commonly abbreviated as IBD) are chronic inflammatory conditions of the bowels. Both the small and the large intestine may be affected in an inflammatory bowel disease. This condition is thought to be associated with autoimmune factors.

Apart from rectal bleeding, other signs and symptoms of inflammatory bowel disease include abdominal cramps, a continuous urge to have a bowel movement (technically referred to as tenesmus), presence of mucus in stools, loss of appetite, weight loss, and anemia.


Polyps are benign growths that may arise from the walls of the colon and the rectum. In many cases, polyps do not produce any noticeable signs and symptoms for an extended period of time. After a long time, signs and symptoms such as diarrhea, constipation, and blood in stool may appear.

Polyps could be of varying sizes. A large polyp is capable of causing obstruction in the lumen of the colon or the rectum. This could lead to constipation and pencil-thin stools. Although most polyps are benign in nature, there is always a possibility that some of them may turn malignant (cancerous).


Blood in the stool may also occur due to rectal or colon cancers. Initially, rectal bleeding in these serious conditions may appear during or after a bowel movement. In time, rectal bleeding may begin to occur continuously. Apart from bleeding from the rectum, colon and rectal cancers may also display other signs and symptoms such as discomfort in the lower abdominal region, persistent constipation, persistent diarrhea, weight loss, and fatigue.


Sometimes, the walls of the intestine may have small pouch-like outgrowths emanating from them. These pouches growing from the walls of the intestine are referred to as diverticula. Feces and bacteria may get trapped within these diverticula during their movement down the intestinal tract.

These diverticula do not produce any symptoms until they become inflamed. The inflammation of diverticula is technically referred to as diverticulitis. This condition may cause rectal bleeding, nausea, fever, changes in bowel movements and pain in the abdomen. Diverticulitis usually resolves on its own within a few days or weeks.

Ischemic colitis

Ischemic colitis refers to an inflammation of the colon (large intestine) that is caused by an inadequate blood supply to this tissue. It is more common in the elderly population.

Rectal prolapse

Rectal prolapse refers to a condition in which the walls of the rectum protrude out of the anal opening. Rectal prolapse may be partial or complete. Rectal bleeding, mucus in the stools, difficulty in defecation, and fecal incontinence are some of the features associated with rectal prolapse.


A fistula refers to any abnormal connection between two hollow spaces within the body. A fistula may form between the rectum and other nearby hollow organs such as the vagina and the components of the urinary system.

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