Font Size

Gastrointestinal Bleeding (cont.)

What are causes of lower GI bleeding?

  • Diverticulosis: One of the most common causes of lower GI bleeding. Small out-pockets, or diverticula, form in the wall of the colon (large intestine), usually in a weakened area of the bowel wall. The person may develop several pockets, which are more common in people who have constipation and strain during a bowel movement.
  • Cancers: One of the early signs of colon or rectal cancers may be blood in the stool.
  • Inflammatory bowel disease (IBD): Flares of inflammation from IBD (Crohn's disease and ulcerative colitis) often cause mucousy stool that has blood mixed in it.
  • Infectious diarrhea: Some viruses or bacteria can cause damage to the inner lining of the intestines, which can lead to bleeding.
  • Angiodysplasia: Along with diverticulosis, this is one of the most common causes of lower GI bleeding. Angiodysplasia is a malformation of the blood vessels in the wall of the GI tract. These are most commonly in the large intestine and often bleed. The elderly and people with chronic kidney failure develop the disease most often.
  • Polyps: Intestinal polyps are noncancerous tumors of the GI tract, occurring mostly in people older than 40 years of age. A small proportion of these polyps may transform into cancer. Colon polyps may bleed rapidly, or they may bleed slowly and go undetected.
  • Hemorrhoids and fissures: Hemorrhoids are swollen veins in and around the anus. Repeated stretching from straining during bowel movements causes them to bleed. Bleeding from hemorrhoids is usually mild, intermittent, and bright red. Anal fissures, or tears in the anal wall, also may trigger small amounts of bright red bleeding from the anus. Forceful straining during passage of hard stool usually causes such tears, which can be very painful and may require surgery.
Medically Reviewed by a Doctor on 7/31/2015
Medical Author:

Must Read Articles Related to Gastrointestinal Bleeding

Anal Fissure
Anal Fissure Anal fissures are small tears in the skin overlying the anus. Anal fissures are generally caused by constipation, or straining with a bowel movement. Symptoms o...learn more >>
Esophageal Cancer
Cancer of the Esophagus The esophagus is a muscular tube measuring 20-25 cm (8-10 in) long and 2-3 cm (0.75-1.25 in) wide that serves as a conduit for moving food and drink from the ....learn more >>
Cancer of the Small Intestine
Cancer of the Small Intestine The small intestine, or small bowel, lies between the stomach and the colon. The small intestine is about 6 m (20 ft) long. Its primary function is to digest an...learn more >>

Patient Comments & Reviews

The eMedicineHealth doctors ask about Gastrointestinal Bleeding (GI):

Gastrointestinal Bleeding - Causes

What was the cause of your gastrointestinal bleeding?

Gastrointestinal Bleeding - Experience

Please share your experience of gastrointestinal bleeding.

Gastrointestinal Bleeding - Symptoms

What were your symptoms of GI bleeding?

Gastrointestinal Bleeding - Treatment

What was the treatment for GI bleeding?

Read What Your Physician is Reading on Medscape

Upper Gastrointestinal Bleeding »

Acute gastrointestinal (GI) bleeding is a potentially life-threatening abdominal emergency that remains a common cause of hospitalization.

Read More on Medscape Reference »

Medical Dictionary