Rectal Bleeding

Rectal bleeding is blood coming out of the anus. Blood color from rectal bleeding varies: bright red, red, maroon, dark tarry, black, or invisible. Any part in the GI tract can result in the rectal bleeding depending the amount and source of bleeding. Here, we mainly discuss about rectal bleeding from the colon or rectum.

Causes and Risk Factors

The most common ones are:

Symptoms and Signs

The common symptoms and signs are:

  • Rectal pain
  • Abdominal pain
  • Visible blood from anus
  • Invisible blood from anus but positive occult blood test
  • Weakness
  • Fatigue
  • Low blood pressure
  • Rapid heart beat
  • Dizziness, lightheadedness
  • Fainting
  • Confusion

Diagnosis and Treatment

Rectal bleeding is usually a medical urgency or emergency. Call 911 to seek emergent medical assistance if you have rectal bleeding and any of the following:

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

Have someone drive you to urgent care or the emergency room to seek immediate medical attention if you have rectal bleeding and any of the following:

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

Diagnosis is based on clinical presentation with one or more of the following tests:

Treatment is based on the causes, risk factors, patient medical condition, etc. One or more of the following modalities are used:

  • Medical therapy, including iv hydration, blood transfusion, medicines, etc
  • Endoscopy
  • Sigmoidoscopy
  • Colonoscopy
  • Surgery


  1. PubMed.
  2. Wikipedia.
  3. Mayo clinic online health information.
  4. Sleisenger and Fordtran's Gastrointestinal and Liver Disease- by Mark Feldman MD, et al.
  5. The Little Black Book of Gastroenterology-by David W. Hay.
  6. Principles of Clinical Gastroenterology by Tadataka Yamada, et al.