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    Bleeding in the Digestive Tract: Why It Happens

    Why Does It Happen? continued...

    Intestinal ulcers are usually caused by excess stomach acid and infection with Helicobacter pylori.

    Cancer of the stomach.

    Bleeding from the lower digestive tract (colon, rectum, and anus) can be caused by:

    Hemorrhoids. These are probably the most common cause of visible blood in the lower digestive tract, especially blood that appears bright red. Hemorrhoids are enlarged veins in the anal area that can rupture and produce blood, which can show up in the toilet or on toilet paper.

    Anal fissures. Tears in the lining of the anus can also cause bleeding. These are often very painful.

    Colon polyps. These are growths that can happen in the colon. Some can turn into cancer over time. Colorectal cancer can also cause bleeding.

    Intestinal infections. Inflammation and bloody diarrhea can result from intestinal infections.

    Ulcerative colitis. Inflammation and extensive surface bleeding from tiny ulcerations can be the reason for blood showing up in the stool.

    Crohn's disease is an immune system condition. It causes inflammation and can result in rectal bleeding.

    Diverticular disease is caused by diverticula -- little “pouches” that bump out from the colon wall.

    Blood vessel problems. As you age, issues may crop up in the blood vessels of the large intestine, which may cause bleeding. It’s not a normal part of getting older, but it is more likely later in life.

    Ischemic colitis. This means that not enough oxygen is getting to the cells that line the intestine. Bloody diarrhea, often accompanied by belly pain, can happen if not enough blood gets to the intestine, which results in ischemia, or insufficient oxygen, and damage to cells lining the intestine.

    What Are the Symptoms?

    These include:

    • Bright red blood coating the stool
    • Dark blood mixed with the stool
    • Black or tarry stool
    • Bright red blood in vomit
    • "Coffee-grounds" appearance of vomit

    Other signs, which also need a doctor’s attention, include:

    • Fatigue, weakness, pale appearance
    • Anemia -- your blood is low on iron-rich hemoglobin

    The location of the bleeding may affect what you notice.

    If it comes from the rectum or the lower colon, bright red blood will coat or mix with your stool. The stool may be mixed with darker blood if the bleeding is higher up in the colon or at the far end of the small intestine.

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