Rectal Bleeding (Blood in the stool)

What is rectal bleeding?

Rectal bleeding refers to any blood that passes from the anus.  It is usually quite an alarming symptom but is actually a very common problem.  It occurs in approximately 10% of the population each year.  The cause of bleeding usually isn’t serious but it’s important to see you GP should it occur.

“Anal canal” type bleeding is usually bright red blood which is noticed on the toilet paper.  On occasion blood can drip from the anus, but more often heavier bleeding is noticed when blood is seen around the toilet pan or when the toilet water is stained red.  In general terms this type of bleeding has occurred somewhere near the anus.

“Rectal bleeding” is when the blood is slightly darker, sometimes with clots, or mixed in with the stool.  Often this implies the bleeding is coming from the inside the bowel.  Sometimes the stools can be very dark plum colour or black, this is called “melaena”.

What will your GP do?

Your GP will take a history and ask you some questions about the nature of the bleeding, any other associated symptoms such as a change in bowel habit or anal pain, and will likely examine both your abdomen and your bottom end.  This involves inspecting the perianal skin and then putting a gloved lubricated finger inside the rectum.  Although this sounds embarrassing it is a quick and painless examination.

Your GP may refer you to a consultant colorectal (bowel) surgeon (such as myself) if he or she feels further examinations and tests are needed.

What tests may you require?

As your specialist colorectal surgeon I will see you in the outpatient clinic and based on your history and examination findings will arrange further tests. 

In the outpatient clinic you will likely require a “proctoscopy”.  This is a small camera that is placed into the anus and allows direct visualisation of the anal canal and in particular of any haemorrhoids present.    Sometimes a “rigid sigmoidoscopy” is also undertaken in the outpatient setting.  This allows immediate inspection of the lower part of the bowel, the rectum. 

Lower gastrointestinal endoscopy is usually required to exclude serious underlying disease.  A flexible sigmoidoscopy inspects the left colon and rectum only, or colonoscopy is used to inspect the whole of the colon.  The choice of test depends on the history and examination findings and will be discussed with you in the outpatient clinic.

What are the causes of rectal bleeding?

The following list is some of the causes of rectal bleeding.  However, you should not try to diagnose yourself.  Always see your GP for medical advice.

Potential causes of rectal bleeding:

Benign Causes

  • Haemorrhoids (piles)
  • Anal fistula
  • Anal fissure
  • Diverticular disease
  • Angiodysplasia
  • Gastroenteritis
  • Inflammatory bowel disease (ulcerative colitis or Crohns disease)
  • Benign bowel polyps (adenoma’s)

Cancer and Malignancy

  • Anal cancer
  • Colorectal (bowel) cancer

Is it colorectal or bowel cancer?

Bowel cancer is the diagnosis that many people with rectal bleeding fear.  Rectal bleeding can be a symptom of bowel cancer.  However the majority of the time rectal bleeding is caused by a benign condition.

If your doctors suspects bowel cancer you will likely be referred via the NHS two week wait suspected colorectal cancer pathway (

Alternatively if you prefer you could be referred privately and receive specialist colorectal consultant care, with myself, throughout each stage of your pathway and investigation.




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