Blood in poo

Do not assume blood in poo is piles

Blood in poo — also called rectal bleeding — is common and is often caused by benign conditions such as haemorrhoids (piles) or anal fissures. However, bowel cancer can present with identical symptoms, especially alongside a change in bowel habit. Every episode of unexplained rectal bleeding deserves GP assessment rather than self-diagnosis.

What blood in poo may look like

Bright red blood may appear on the toilet paper after wiping, drip into the toilet bowl, or coat the outside of the stool. This usually indicates bleeding from the lower bowel — the anus, rectum or lower colon — and common causes include piles, fissures and diverticular disease.

Dark red or black tar-like stools (melaena) are sticky, foul-smelling and black. They suggest bleeding from the upper gut — the stomach or small intestine — and need urgent medical assessment, so call NHS 111 or go to A&E.

Blood mixed through the stool, appearing maroon or dark throughout, may indicate bleeding from higher in the colon. This always needs investigation.

Common causes of blood in poo

Haemorrhoids (piles) are swollen blood vessels in or around the anus. They are very common and cause bright red bleeding, itching and lumps.

An anal fissure is a small tear in the anal lining. It causes bright red blood and sharp pain when passing stool.

Diverticular disease involves small pouches in the colon wall that can sometimes bleed. Inflammatory bowel disease, which includes Crohn’s disease and ulcerative colitis, causes bleeding alongside diarrhoea and abdominal pain.

Polyps are growths on the bowel lining, and some can become cancerous over time. Bowel cancer may cause bleeding as its only symptom, especially early on, and is also associated with a change in bowel habit, weight loss, abdominal pain and iron deficiency anaemia.

When to see a GP about blood in poo

See a GP for any unexplained blood in poo — even a single episode.

Book an urgent appointment if:

• the bleeding comes with a change in bowel habit lasting three weeks or more
• you have unexplained weight loss
• you have persistent abdominal pain
• you are over 40 with rectal bleeding — do not assume piles without an examination
• blood tests have shown iron deficiency anaemia

NHS bowel cancer screening

The NHS sends FIT (faecal immunochemical test) kits to eligible adults to detect hidden blood in stool. A positive result does not mean cancer, but it needs follow-up — usually a colonoscopy. Screening finds cancer early, when treatment is most effective, so complete your kit when it arrives.

What a GP may do about rectal bleeding

A GP will usually examine your abdomen and may perform a rectal examination. They can arrange blood tests, such as a full blood count and iron studies, and refer you for a colonoscopy or flexible sigmoidoscopy if indicated.

If there are no red flag features, confirmed piles or fissures can be treated directly.

When rectal bleeding is an emergency

Call 999 or go to A&E if:

• you are passing a large volume of blood from the rectum
• you feel faint or dizzy with the bleeding
• you have severe abdominal pain
• your stools are black and tar-like

Red flag symptoms alongside rectal bleeding

Seek prompt assessment if:

• your stools are looser, or you are going more often, for three weeks or more
• you feel that your bowel is not emptying completely
• you have lost weight without explanation
• you feel fatigued because of anaemia
• you can feel a lump in your abdomen or rectum

These features increase concern for bowel cancer regardless of age.

If you have been told you have piles

Even confirmed piles can coexist with other conditions. If bleeding continues despite treatment for piles, or your bowel habit changes, return to your GP for reassessment.

Common questions about blood in poo

What does blood in poo look like?

Bright red blood on toilet paper, dripping into the bowl, or coating the surface of stool usually comes from the anus or lower rectum. Dark red or black tar-like stools (melaena) suggest bleeding from higher in the stomach or intestine — this needs urgent assessment.

What are the most common causes of blood in poo?

The most common causes are haemorrhoids (piles), anal fissures (small tears), diverticular disease, inflammatory bowel disease, polyps and bowel cancer. Piles are common, but they should be diagnosed rather than assumed, especially if you are over 40.

Could blood in poo be bowel cancer?

Yes. Bowel cancer can cause rectal bleeding, often with a change in bowel habit — looser stools, going more often, or feeling the bowel is not fully empty. It is more common over 50 but can occur younger. Early diagnosis improves outcomes significantly.

What is bowel cancer screening?

In England, people aged 60 to 74 (expanding to 50) receive home faecal immunochemical test (FIT) kits every two years to detect hidden blood. A positive result needs follow-up colonoscopy — it does not mean cancer, but needs investigation.

When is rectal bleeding an emergency?

Rectal bleeding is an emergency when there is large-volume bleeding, fainting, severe abdominal pain, or black tar-like stools — these need urgent hospital assessment. Moderate ongoing bleeding also needs same-day medical advice.

Sources

• NHS — Bleeding from the bottom (rectal bleeding)
• NHS — Bowel cancer