The presence of blood during or after a bowel movement can be a worrying sign but most cases are not as serious as it may appear. It is important to differentiate between blood in the stool, either fresh (red) or old (dark), and blood only upon wiping the anus after a bowel movement.

Profuse bleeding within the lower part of the gastrointestinal tract may mess the toilet bowl with bright red blood and immediate medical attention should be sought. The presence of blood on tissue paper after wiping is more often due to hemorrhoids than other more serious causes.

It is important to take note of other signs or symptoms that accompany rectal bleeding during or after a bowel movement. This may include :

Persistent rectal bleeding and unintentional weight loss, even without any of the other signs and symptoms above, needs to be investigated immediately.

Causes of Rectal Bleeding After a Bowel Movement

Hemorrhoids (Piles)

  • Inflamed and enlarged veins in the lower rectum and/or anus.
  • Other symptoms may include an itchy anus, pain and a palpable sensitive lump in the anal area.

Anal fissure

  • Tiny tears on the skin of the anus most commonly caused by constipation or chronic diarrhea.
  • Other symptoms include an itchy anus, pain during and after passing stool and visible tears around the anus.

Inflammatory Bowel Disease

  • Chronic inflammation of the small and/or large intestine as a result of autoimmune factors.
  • Other symptoms include tenesmus (urging to have a bowel movement), stomach cramps and abdominal pain, bloody diarrhea or mucus in stool. Anemia, weight loss and a lack of appetite may also be reported in severe cases.

Polyps

  • Polyps in the rectum or colon are growths from the lining of these areas that are mostly benign, although some may become cancerous over time.
  • Polyps may be asymptomatic for long periods of time. Eventually symptoms like rectal bleeding, red blood in the stool, constipation or diarrhea may become evident. Narrowing of the stool followed by severe constipation may be an indication of a large polyp blocking the lumen of the colon or rectum.

Cancer

  • Cancer of the colon or rectum may cause rectal bleeding during and after a bowel movement, and eventually a constant rectal bleed.
  • Other symptoms may include persistent diarrhea or constipation, lower abdominal discomfort, fatigue and unintentional weight loss.

Other Causes of Rectal Bleeding

  • Diverticulitis
  • Ischemic colitis
  • Rectal prolapse
  • Fistulas

Article reviewed by Dr. Greg. Last updated on December 24, 2010