Why do I bleed when I poo? Causes of rectal bleeding explained
Seeing blood when you open your bowels can be alarming, but in many cases, the cause is benign and easily treatable.
This article explains the most common reasons for rectal bleeding, when it’s nothing to worry about, and when it’s important to seek further assessment.
What does rectal bleeding look like?
Rectal bleeding can present in different ways, including:
Bright red blood on the toilet paper
Blood in the toilet bowl or on the stool
Darker blood mixed through the stool
Blood with mucus or discharge
The colour and pattern of bleeding can sometimes give clues about the underlying cause, although this is not always reliable.
What are the most common causes?
The majority of people who notice blood when they open their bowels have a benign (non-cancerous) condition. Common causes include:
Haemorrhoids (piles)
Haemorrhoids are swollen veins in the anal canal and are one of the most common causes of bright red bleeding. Bleeding is often painless and may be noticed on the toilet paper or dripping into the bowl.
Anal fissures
A fissure is a small tear in the lining of the anus, often caused by passing hard stools.
This typically causes sharp pain during or after a bowel movement or intercourse, along with small amounts of bright red blood.
Irritation or inflammation
Conditions such as diarrhoea, excessive wiping, or local skin irritation can lead to minor bleeding.
Could it be something more serious?
While most causes are benign, rectal bleeding can occasionally be a sign of more serious conditions, including:
Bowel (colorectal) cancer
Inflammatory bowel disease (IBD) such as Crohn’s disease or ulcerative colitis or other causes of bowel inflammation
Polyps (growths in the bowel)
These are less common, but it’s important not to ignore persistent or unexplained bleeding.
When should I be concerned?
You should seek medical advice if you experience:
Ongoing or recurrent bleeding
Blood mixed within the stool (rather than just on the surface)
A change in bowel habits (diarrhoea, constipation, or narrower stools)
Unexplained weight loss
Persistent pain or a lump
Iron deficiency or unexplained fatigue
A strong family history of cancers, especially bowel
If you are concerned about blood in your stool, you should make an appointment to see your GP. Even if the cause turns out to be something simple, it’s always worth having it properly assessed.
Do I need any tests?
Not everyone with rectal bleeding will need extensive testing. Your doctor may begin with:
A history and examination
A digital anorectal examination (DARE)
Stool tests to look for evidence of blood in the poo
Blood tests looking for signs of iron deficiency or anaemia (low blood count)
Depending on your symptoms and risk factors, your GP may refer you to a surgeon or gastroenterologist for consideration of a colonoscopy or a flexible sigmoidoscopy (mini-colonoscopy that doesn’t view the entire colon). These tests are a definitive way of identifying the cause and ruling out more serious conditions. Sometimes, depending on the colour of the stool and your symptoms, a gastroscopy (camera into the stomach and first part of the small bowel) will also be an option.
Dr Matt Marino performs colonoscopy, gastroscopy and high-resolution anoscopy to assess causes of rectal bleeding.
Can rectal bleeding be prevented?
Simple measures can help reduce the risk of bleeding if it is from a benign cause. These include:
Avoid straining on the toilet
Maintain a high-fibre diet (simple supplementation with Benefibre or psyllium husk is a good idea)
Stay well hydrated
Avoid prolonged sitting on the toilet
Treat constipation early with whatever laxative works for you
These steps are particularly helpful for avoiding/treating haemorrhoids and fissures.
What should I do if I notice bleeding?
The most important thing is not to ignore it.
While rectal bleeding is often due to something minor, it’s not possible to be certain without proper assessment. Early evaluation can provide reassurance and, where needed, allow for timely treatment.
Summary
Rectal bleeding is common and often caused by common, non-worrying conditions
Bright red blood is usually from the lower bowel or anus
Pain with bleeding may suggest a fissure, while painless bleeding is often from haemorrhoids
Most causes are benign, but persistent or unusual bleeding should always be checked
Early assessment helps rule out serious conditions and provides reassurance
How we can help
If you’re experiencing bleeding when you open your bowels, Dr Matt Marino can provide a thorough evaluation and guide you through appropriate management. He is a Melbourne based colorectal and general surgeon who performs colonoscopy and gastroscopy and has a modern approach to the management of haemorrhoids, fissures, and a wide range of colorectal conditions, and accepts referrals from your GP.
If you are experiencing blood in your stool, you are welcome to arrange a consultation with Dr Matt Marino. Contact us here or call on 0493 318 188 to book an appointment.
