After you have used the toilet, you might see blood in your poo (stool), spotting on the toilet paper or drops in the toilet bowl. Many people dismiss this as nothing or they are too embarrassed to seek help. But blood in your stool can indicate a range of problems, some of which are very serious.

If you have blood in your stools 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 heavy rectal bleeding and also have bad stomach pains.

What does blood in stools look like?

Blood from your stool could look bright red, or it might be dark red or black.

How the blood looks depends on where it is coming from.

Spots of red blood on the toilet paper, drops in the toilet bowl, blood on the surface of your stool or in your underwear indicate the bleeding is coming from the anus or lower rectum.

If the blood is mixed in with your stool, this suggests bleeding might be from higher up in the bowel.

If your stools are black and like tar, and they smell bad, this is also probably because the blood is coming from higher up in the bowel.

What causes blood in stools?

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

• haemorrhoids
• anal fissures, which are small painful cracks in the anus
• bowel infections
• bowel cancer
• colorectal polyps, which are small growths that can become cancerous
• inflammatory bowel disease (Crohn's disease and ulcerative colitis)
• diverticular disease
• fistula (an abnormal opening in the rectum or anus)
• prolapse (when part of the rectum sticks out of the anus)
• an injury

When should I see a doctor?

If you have any blood in your stool or bleeding from the anus, make sure you get it checked out by a doctor.

As well as blood in your stool, you might have other symptoms that could indicate something more serious is going on.

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.

If you are losing weight and have blood in your stool, this suggests an illness that needs treatment. See your doctor as soon as possible.

If you received some trauma to the area, you might have an injury or a foreign object in the area. Seek an examination from your doctor as soon as possible.

What tests are used to find the cause of blood in stools?

Your doctor will talk to you, examine you, and should arrange some tests to investigate the cause. The doctor will choose the right test for you based on your age, symptoms and medical history. Possible tests include:

• rectal examination — your doctor or nurse looks and feels around your rectum, anal canal and nearby organs, such as the prostate and bladder
• anoscopy — a procedure where your doctor will use a camera in a tube to view the last 5cm of your anus and lower rectum
• sigmoidoscopy — a procedure where your doctor uses a camera to check inside your rectum and most of your lower large intestine (‘sigmoid colon’)
• colonoscopy — a physician uses a camera that sits within a tube to examine your entire colon
• gastroscopy — a tube is inserted through the mouth to look at the oesophagus, stomach and first part of the small intestine

Some of these tests are done under sedation and anaesthetic. Ask your doctor for more information.

How is blood in stools treated?

The right treatment for blood in your stool depends on what is causing the problem.

If it is caused by haemorrhoids or an anal fissure, the treatment could be to make changes to your lifestyle or diet. Sometimes surgery is needed.

If the bleeding is due to a haemorrhage, for example if you have diverticular disease, you may need emergency surgery.

Polyps may be removed during a colonoscopy. If you have bowel cancer, you might need more urgent and invasive treatment such as surgery, chemotherapy, radiotherapy or other treatments.