Bleeding in the Bowels – Causes, Diagnosis, Treatment

Bleeding can occur in any part of gastrointestinal tract. When bleeding occurs in the upper part of gastrointestinal tract (such as from the mouth, throat, esophagus, and stomach), blood may be visible in vomitus. In contrast, bleeding from the lower part of gastrointestinal tract (like in the small intestine, large intestine, rectum or anus) is only apparent in the feces.

Is bowel bleeding serious?

In many cases, bleeding in the bowels is not copious, and the sites of the bleeding may be quickly repaired by the body’s own mechanisms. In such cases, blood in stools may not be visible with the naked eye and a person may not even know that there is any bleeding. Such hidden blood (also known as occult blood) can only be identified through laboratory tests, such as the fecal occult blood test (abbreviated as FOBT).

Tests for occult blood are not done routinely. They are only prescribed if internal bleeding in bowels is suspected. At other times, blood may be easily visible in stool and toilet water after a bowel movement. Bleeding in bowels can occur due to a variety of causes. For example, bleeding may be a result of piles, which is not life threatening. Or bleeding may occur due to cancer, which is a serious, life-threatening condition.

Both visible and occult blood in stools may or may not represent a serious underlying condition. Nevertheless, the cause of the bleeding has to be investigated.

Signs and Symptoms

Bleeding in bowels is a sign of injury in intestine. The following are some of the common signs and symptoms that may accompanying bleeding in bowels.

Visible blood in stools

The most obvious sign of bleeding in bowels is the presence of visible blood in stools. One may notice blood on tissue wipes after completing a bowel motion. Blood may also be seen in toilet water after defecation. The most common reason for the presence of fresh blood in stools is hemorrhoids in the anal region. Even though one may get scared seeing fresh blood in stools, hemorrhoids are not life-threatening. Other accompanying signs and symptoms (such as abdominal pain) should also be noted.

Dark, tarry stools

Sometimes, the blood in stools may turn it into a black and tarry mass. This usually indicates bleeding in the upper part of bowels. The black color is caused by metabolic and microbial breakdown of hemoglobin from red blood cells.


Anemia is a result of excessive loss of blood. The excessive loss may occur in a short span of time, caused by massive blood loss. Alternatively, a lot of blood can be lost through small amounts of bleeding over a long period of time. Apart from low number of red blood cells, anemia is also characterized by pale skin, shortness of breath and fatigue.

Itching and pain

Abdominal pain may also accompany bleeding in bowels. Itching, pain or a burning sensation in anal region may also be felt in case of blood loss due to hemorrhoids (also known as piles). A lingering feeling of incomplete bowel motion may also be present in case of hemorrhoids.

Depending on the underlying cause of bleeding in bowels, other signs and symptoms may also be present.

Causes of Bleeding in Bowels

Bleeding in the bowels can result from a number of different causes. The following are some of the more common causes.

Peptic ulcer

Peptic ulcer disease refers to the presence of open sores in the inner lining of upper gut (stomach and duodenum). Some of the ulcers can bleed, resulting in (occult) blood in the stools. Bleeding due to peptic ulcer disease is mostly caused by infection of the upper gut with the bacteria, Helicobacter pylori (abbreviated as H. pylori). Overuse of certain medicinal drugs may also cause bleeding from peptic ulcer disease.


Hemorrhoids (or piles) are a very common cause of blood in stools. Hemorrhoids refer to swollen veins in rectum and anal regions. These swollen veins cause itching, burning sensation and pain during bowel movements. Rupture of these swollen veins during bowel movements causes bleeding.


Diverticula are outpouches formed in the walls of colon. It is common in the elderly. Infection and inflammation of these diverticula may result in bleeding.

Inflammatory bowel disease

Inflammatory bowel disease (such as Crohn’s disease) is an autoimmune condition that causes inflammation of bowels. Bleeding may also occur in this condition, usually from ulcers formed in the walls of gut.

Cancer of bowels

Cancer refers to unregulated growth of cells in certain regions of the body. Cancer in bowels is most frequently seen in colon and rectum. Not all cancerous growths will cause bleeding. Bleeding caused by cancer of bowels can be detected in stools. It is important to note that cancer of bowels is not as common as the above mentioned reasons for bleeding in bowels.

Other causes

Apart from the above mentioned common causes of bleeding in bowels, other conditions may also contribute to blood in stools. Some of the less common causes of blood in stools include anal fistula, pancreatitis, polyps, arteriovenous malformations, gastritis, excessive alcohol consumption, Mallory-Weiss tear, bleeding disorders, toxins, and trauma.

Diagnosis and Treatment

Sometimes the blood in stools is clearly visible. At other times, a doctor might suspect bleeding in bowels, even when no visible blood is seen in stools. In such cases, the doctor will prescribe laboratory tests to confirm the presence of occult blood in stools. The stool analysis will test for blood, lymphocytes (or white blood cells), eggs of parasites, microbes, antibodies and other proteins.

If the presence of blood is confirmed in the fecal occult blood test, imaging studies may be conducted to identify the sites of lesions in gut. For example, to visualize the inside walls of colon (large intestine), colonoscopy is performed. Enteroscopy is used to visualize the interior walls of small intestine. Upper GI endoscopy is performed to identify the sites of bleeding in upper gastrointestinal tract. Other laboratory tests may be done to identify the cause of bleeding in bowels.

Once the cause of bleeding in bowels is identified, an appropriate treatment is determined. The chosen treatment will vary based on the cause. Treatment may include medications, dietary changes, lifestyle changes, and surgery. Surgery is required in cases where excessive bleeding needs to be stopped as soon as possible, regardless of the cause of bleeding.

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