What is blood in stool (poo)?

You might see blood in your stool (poo) after using the toilet. You may also see spots of blood on the toilet paper or drops of blood in the toilet bowl.

A small amount of bleeding just once is usually not serious. But it's best to see your doctor for a check-up. Seeing blood in your stool can mean different health problems, and some of them can be very serious.

What symptoms are related to blood in stools?

Blood in your stool can be bright red, dark red or black. The colour of the blood depends on where it is coming from.

Spots of red blood suggest that the bleeding is coming from your large intestine or rectum.

If the blood is dark red and mixed in with your poo, it may come from higher up in your bowel, like your colon or small intestine.

If your stools are black like tar, and smell bad, the blood is probably coming from higher up in your gastrointestinal tract.

What causes blood in stools?

Blood in your stool can be caused by many different things. These include:

• anal fissures, which are small painful cracks in the anus
• haemorrhoids
• gastroenteritis (tummy bug)
• diverticular disease
• inflammatory bowel disease — Crohn's disease or ulcerative colitis
• polyps, which can be an early sign of bowel cancer

Very dark or black blood or stool can be caused by:

• bleeding in your stomach
• stomach ulcer
• side effects of medicines such as warfarin (a blood thinner)

Sometimes your stool can look very dark or black if you:

• take iron tablets
• eat a lot of dark foods like liquorice and blueberries

It's a good idea to have your doctor or pharmacist review your medicines if you have blood in your stools or dark stools.

How is the cause of blood in stools diagnosed?

Your doctor will ask you about your symptoms. They may also examine you and send you for blood tests. These might include:

• a rectal examination — your doctor checks your bottom with a gloved finger
• blood tests
• stool (poo) tests

Your doctor may also refer you to a specialist for further tests, such as a:

• sigmoidoscopy — a flexible tube with a camera on the end is used to check inside your rectum and your lower large intestine (also called the sigmoid colon)
• colonoscopy — a flexible tube with a camera on the end is used to examine your entire colon
• gastroscopy — an endoscope (flexible tube with a camera on the end) is used to look at your oesophagus (food pipe), stomach and first part of your small intestine

Some of these tests are done under sedation. You may need to go to hospital.

When should I see a doctor?

If you have blood in your poo, you should see your doctor. Most reasons for having blood in your poo are not serious. But blood in your stool can sometimes be a sign of bowel cancer. It's easier to treat this if it's found early.

Always see your doctor if you have blood in your stools, even if you know what caused it before.

Ask for an urgent doctor's appointment if:

• your poo is dark red or black
• you have bloody diarrhoea

You should also see your doctor if you:

• have a change in how often you poo or there is a change in the texture of your poo
• have abdominal pain
• feel very tired or weak

When to seek urgent care

If you have blood in your stool and you feel faint, dizzy or light-headed, this may be an emergency. Go to the nearest emergency department as soon as possible or call triple zero (000) and ask for an ambulance.

Go to the emergency department if:

• you have bleeding that will not stop
• there's a lot of blood — the toilet water is red or there are large blood clots

How is blood in stools treated?

Treatment of blood in your stools will depend on what is causing it.

Self-care at home

Some causes of bleeding, like haemorrhoids or anal fissures, can be helped or prevented by changes to your lifestyle or diet.

You might find it helpful to:

• drink plenty of water
• eat a healthy and varied diet
• keep active
• go to the toilet when you need to and avoid straining

Bowel cancer screening

It's important to have screening tests for bowel cancer as you get older.

Bowel cancer screening tests are sent to all Australians aged between 50 and 74 years. If you are aged between 45 and 49 years, you can request your first free bowel cancer screening test. This happens as part of the National Bowel Cancer Screening Program.

Resources and support

Read more about bowel cancer symptoms on the Cancer Australia website.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.