Blood in Your Stool: When Should You Be Concerned?

Blood in your stool can be caused by several conditions, from haemorrhoids to bowel disease. Learn the causes and when to seek medical advice.
August 8, 2026

Finding blood in your stool can be alarming. While it is often caused by relatively common and treatable conditions, it can sometimes be a sign of a more serious digestive problem that requires investigation. Understanding the possible causes and knowing when to seek medical advice is important for protecting your long-term health.

What Causes Blood in Stool?

Blood in the stool, also known as rectal bleeding, can originate from various parts of the digestive tract. Some of the most common causes include:

  • Haemorrhoids (piles)
  • Anal fissures
  • Diverticular disease
  • Inflammatory bowel disease (IBD)
  • Infections affecting the digestive system
  • Colon polyps
  • Colorectal cancer
  • Injury or irritation to the lining of the digestive tract
  • Certain medications, including blood thinners

While some causes are minor, others require prompt diagnosis and treatment. This is why any unexplained rectal bleeding should be assessed by a healthcare professional.

What Does the Colour of the Blood Mean?

The appearance of the blood can sometimes provide clues about where it is coming from within the digestive system.

Bright Red Blood

Fresh, bright red blood is often associated with conditions affecting the lower bowel, rectum or anus, such as haemorrhoids or anal fissures. However, it can also be caused by polyps or bowel cancer.

Dark Red Blood

Darker blood may indicate bleeding higher within the colon and should always be investigated further.

Black or Tarry Stools

Black, sticky stools can suggest bleeding higher up in the digestive tract, such as the stomach or small intestine, and require urgent medical assessment.

Is Occasional Rectal Bleeding Serious?

Many people assume that if blood only appears occasionally, there is nothing to worry about. However, intermittent bleeding should never be ignored.

Some digestive conditions, including bowel cancer and colon polyps, may bleed on and off. Even if the bleeding stops, it is important to identify the underlying cause rather than assume the problem has resolved itself.

Other Symptoms to Watch For

Blood in the stool may occur alongside other symptoms that could indicate a more significant digestive condition, including:

  • Changes in bowel habits
  • Persistent abdominal pain
  • Unexplained weight loss
  • Fatigue or anaemia
  • Feeling light-headed or dizzy
  • Ongoing diarrhoea or constipation
  • Nausea or vomiting

If you experience any of these symptoms alongside rectal bleeding, it is important to seek medical advice promptly.

How Is the Cause Diagnosed?

The most effective way to determine the source of rectal bleeding is through a thorough assessment of the digestive tract.

A colonoscopy allows a specialist to examine the lining of the colon and rectum using a flexible camera. It can help diagnose conditions such as:

  • Colon polyps
  • Inflammatory bowel disease
  • Diverticular disease
  • Colorectal cancer
  • Other abnormalities affecting the large bowel

During the procedure, polyps can often be removed and tissue samples can be taken if required.

When Should You Arrange a Colonoscopy?

You should consider seeking specialist assessment if you experience:

  • Any unexplained blood in your stool
  • Recurrent rectal bleeding
  • Changes in bowel habits
  • A family history of bowel cancer
  • Ongoing digestive symptoms without a clear cause

Early investigation can provide reassurance and, where necessary, allow treatment to begin as soon as possible.

Don't Ignore the Warning Signs

Although blood in the stool is not always a sign of a serious condition, it should never be dismissed. Early diagnosis can make a significant difference, particularly when it comes to identifying bowel cancer, colon polyps and other digestive conditions at an earlier stage.

Book a Private Colonoscopy in Birmingham with Gut Diagnostics

At Gut Diagnostics, we provide expert digestive health assessments and private colonoscopy services in Birmingham. Our experienced team offers rapid access to diagnostic investigations, helping identify the cause of rectal bleeding and other bowel symptoms without lengthy waiting times.

If you have noticed blood in your stool or are concerned about your digestive health, contact Gut Diagnostics today to arrange a consultation and learn more about our private colonoscopy services in Birmingham.

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