Definition

Rectal bleeding can refer to any blood that passes from your anus, although rectal bleeding is usually assumed to refer to bleeding from your lower colon or rectum. Your rectum makes up the lower portion of your large intestine.

Rectal bleeding may show up as blood in your stool, on the toilet paper or in the toilet bowl. Blood that results from rectal bleeding is usually bright red in color, but occasionally can be dark maroon.

Causes


Rectal bleeding may occur for many reasons. Common causes of rectal bleeding include:

  1. Anal fissure (a small tear in the lining of the anal canal)
  2. Constipation
  3. Hard stools
  4. Hemorrhoids (swollen and inflamed veins in your anus or rectum)

Less common causes of rectal bleeding include:

  1. Anal cancer
  2. Angiodysplasia (abnormalities in the blood vessels near the intestines)
  3. Colon cancer
  4. Colon polyps
  5. Crohn's disease (a type of inflammatory bowel disease)
  6. Diarrhea
  7. Diverticulosis (a bulging pouch that forms on the wall of the intestine)
  8. Inflammatory bowel disease (IBD)
  9. Ischemic colitis (colon inflammation caused by reduced blood flow)
  10. Proctitis (inflammation of the lining of the rectum)
  11. Pseudomembranous colitis (colon inflammation caused by an infection)
  12. Radiation therapy
  13. Rectal cancer
  14. Solitary rectal ulcer syndrome (a sore on the wall of the rectum)
  15. Ulcerative colitis

When to see a doctor


Call 911 or emergency medical assistance

Seek emergency help if you have significant rectal bleeding and any signs of shock:

  • Rapid, shallow breathing
  • Dizziness or lightheadedness after standing up
  • Blurred vision
  • Fainting
  • Confusion
  • Nausea
  • Cold, clammy, pale skin
  • Low urine output

Seek immediate medical attention

Have someone drive you to an emergency room if rectal bleeding is:

  • Continuous or heavy
  • Accompanied by severe abdominal pain or cramping

Schedule a doctor's visit

Make an appointment to see your doctor if you have rectal bleeding that lasts more than a day or two, or earlier if the bleeding worries you.


Carcinoid tumors

Colon cancer

Colon polyps

Diverticulitis

Hemorrhoids

Plague

Proctitis

Solitary rectal ulcer syndrome

Solitary rectal ulcer syndrome, a rare condition, may be caused by chronic constipation. Dietary changes may help mild cases.

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Ulcerative colitis