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Blood in your stool / rectal bleeding
Blood seen on the toilet paper, in the pan or mixed through the stool — most often from piles or a small tear, but always a symptom that needs checking because it can occasionally be the first sign of bowel cancer.
Education and reference only. This explains the common causes of blood in your stool / rectal bleeding and the warning signs that need urgent help, in plain language — it is not a diagnosis or a substitute for advice from a clinician. If you feel very unwell or are worried, seek medical help.
Quick answer
What is blood in your stool / rectal bleeding?
Rectal bleeding means blood passing from the back passage, and the way it looks offers important clues. Bright red blood that streaks the paper, drips into the pan or coats the outside of an otherwise normal stool usually comes from low down — most often haemorrhoids (piles) or a small tear called an anal fissure.
- Get urgent help: Call 999 or go to A&E for heavy or continuous rectal bleeding, or bleeding with dizziness, fainting, a racing heart or feeling cold and clammy — these are signs of significant blood loss. Seek urgent same-day help for black, tarry, foul-smelling stools, which suggest bleeding from the stomach or upper gut.
- Self-care: If a clinician has confirmed your bleeding comes from piles or a small tear, the mainstay of self-care is keeping stools soft and easy to pass so the area is not strained or torn further.
About blood in your stool / rectal bleeding
Rectal bleeding means blood passing from the back passage, and the way it looks offers important clues. Bright red blood that streaks the paper, drips into the pan or coats the outside of an otherwise normal stool usually comes from low down — most often haemorrhoids (piles) or a small tear called an anal fissure. Blood mixed evenly through the stool, or a change in bowel habit lasting several weeks, points higher up and needs more thorough assessment. Very dark, black, tarry and foul-smelling stools (melaena) are different again: they suggest bleeding from the stomach or upper gut, where blood has been partly digested, and that is an urgent matter. Because rectal bleeding is also the way bowel cancer can first show itself, the firm rule is that any new, persistent or unexplained bleeding from the back passage should always be examined by a clinician rather than assumed to be piles.
When to get help
Call 999 or go to A&E if blood in your stool / rectal bleeding comes with any of these warning signs:
- Call 999 or go to A&E for heavy or continuous rectal bleeding, or bleeding with dizziness, fainting, a racing heart or feeling cold and clammy — these are signs of significant blood loss.
- Seek urgent same-day help for black, tarry, foul-smelling stools, which suggest bleeding from the stomach or upper gut.
- See a doctor without delay for persistent rectal bleeding, blood mixed through the stool, or a lasting change in bowel habit — these always need checking for bowel cancer.
- Seek urgent help for rectal bleeding with severe tummy pain, fever or vomiting.
- See a doctor promptly for rectal bleeding with unexplained weight loss or tiredness.
When to see a doctor
Any new, persistent or unexplained bleeding from the back passage should be seen by a doctor, even if you think it is just piles, because the only way to be sure is to be examined. Arrange an urgent assessment if the bleeding is heavy, if the stools are black and tarry, or if you feel faint, and call 999 if you feel very unwell or the bleeding will not stop. Book a routine appointment for occasional bright red streaks with an obvious cause such as constipation, but go sooner if there is a change in your bowel habit, weight loss or tummy pain, or if the bleeding keeps coming back.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
What can cause it
Common causes of blood in your stool / rectal bleeding
Blood in your stool / rectal bleeding has many possible causes. Each links to a full, plain-language guide to that condition — what it is, how it's treated and when to seek help.
What helps
Self-care and what you can do
If a clinician has confirmed your bleeding comes from piles or a small tear, the mainstay of self-care is keeping stools soft and easy to pass so the area is not strained or torn further. Drink plenty of fluids, eat more fibre such as wholegrains, fruit and vegetables, and avoid straining or sitting on the toilet for long periods. Gentle cleaning with water rather than dry paper, and not delaying when you feel the urge to go, both help the area settle. Keep an eye on the colour and amount of any bleeding and note any change in your bowel habit, as this information helps your clinician — but remember self-care only applies once the cause has been properly checked.
Answers
Blood in your stool / rectal bleeding: frequently asked questions
Is rectal bleeding always cancer?
No — most rectal bleeding comes from piles or a small tear and is not cancer. But because bowel cancer can show itself this way, any new or persistent bleeding from the back passage should always be examined rather than assumed to be harmless.
What does the colour of the blood tell me?
Bright red blood usually comes from low down, such as piles or a fissure. Black, tarry, foul-smelling stools suggest bleeding higher up in the stomach or gut and need urgent assessment. Blood mixed evenly through the stool also needs prompt checking.
When should I worry about blood in my stool?
Seek urgent help for heavy bleeding, feeling faint, or black tarry stools. See a doctor promptly for persistent bleeding, a change in bowel habit, weight loss or tummy pain — these features need investigation.
Can constipation cause rectal bleeding?
Yes. Straining with hard stools commonly causes piles or a small tear, both of which can bleed. Keeping stools soft helps, but a clinician should still confirm the cause if the bleeding is new or keeps happening.
Sources
Where this is drawn from
- NICE CKS: Rectal bleeding.
- Bowel Cancer UK: symptoms of bowel cancer.
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