What are the causes of rectal bleeding (hematochezia)?

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Last updated: April 14, 2025View editorial policy

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From the Guidelines

Rectal bleeding is most commonly caused by hemorrhoids, diverticulosis, angiodysplasia, and colorectal cancer, as evidenced by the most recent study 1.

Causes of Rectal Bleeding

The causes of rectal bleeding can range from mild to serious conditions.

  • Hemorrhoids, which are swollen blood vessels in the rectum or anus, can bleed during bowel movements.
  • Anal fissures, small tears in the lining of the anus, can also cause bleeding.
  • Colorectal polyps or cancer may cause bleeding that appears as bright red blood or darker, tarry stools.
  • Inflammatory bowel diseases like Crohn's disease or ulcerative colitis, diverticular disease, infections, and trauma to the rectum are other potential causes.
  • Certain medications, such as blood thinners (warfarin, aspirin, clopidogrel), can increase the risk of bleeding.

Evaluation and Management

The color of the blood often indicates the source: bright red blood typically suggests a source near the rectum or anus, while darker blood may indicate bleeding higher in the digestive tract. Any rectal bleeding should be evaluated by a healthcare provider, especially if it's persistent, accompanied by pain, changes in bowel habits, unexplained weight loss, or occurs in individuals over 40, as these could indicate more serious conditions requiring prompt medical attention. A complete medical history, physical examination, including a digital rectal examination, and laboratory tests, such as a complete blood count and coagulation assessment, are essential in evaluating patients with rectal bleeding 1. In patients with suspected bleeding hemorrhoids, a focused medical history and physical examination, including a digital rectal examination, should be performed to rule out other causes of lower gastrointestinal bleeding 1. Colonoscopy should be considered in patients with concern for inflammatory bowel disease or cancer arising from patient personal and family history, or from physical examination 1. The use of flavonoids and phlebotonics, such as topical muscle relaxants, may be beneficial in relieving symptoms of complicated hemorrhoids 1. However, the role of NSAIDs, topical steroids, and other topical agents is not well established, and their use should be approached with caution 1.

From the Research

Causes of Rectal Bleeding

  • Rectal bleeding can be caused by various conditions, ranging from benign to life-threatening 2, 3
  • Haemorrhoids are the most common cause of rectal bleeding, but other conditions such as anal fissures, inflammatory bowel disease, and colorectal cancer can also cause rectal bleeding 2, 4, 5
  • In patients with inflammatory bowel disease, such as Crohn's disease and ulcerative colitis, rectal bleeding can be a symptom of the disease 4, 5, 6
  • Other causes of rectal bleeding include premalignant polyps, colorectal cancer, and anal sepsis 2, 3

Risk Factors

  • Age is a significant risk factor for rectal bleeding, with most patients over 40 years old requiring colonoscopy to screen for and treat premalignant polyps and colorectal cancer 2
  • Comorbid conditions, such as inflammatory bowel disease, can also increase the risk of rectal bleeding 4, 5, 6
  • Patients with a family history of colorectal cancer or inflammatory bowel disease may also be at increased risk of rectal bleeding 2, 6

Diagnosis and Treatment

  • A systematic approach to diagnosis, including history, examination, and investigation, is essential for determining the cause of rectal bleeding 2, 3
  • Treatment options vary depending on the cause of rectal bleeding, but may include medical therapy, surgery, or a combination of both 2, 3, 4, 5
  • In patients with inflammatory bowel disease, medical therapy is often the first line of treatment, with surgery reserved for patients who do not respond to conservative measures 4, 5

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Rectal bleeding.

Australian family physician, 2000

Research

Hemorrhoids and anal fissures in inflammatory bowel disease.

Minerva gastroenterologica e dietologica, 2015

Research

Ulcerative Colitis.

Mayo Clinic proceedings, 2019

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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