blood-in-poo-nhs-causes-symptoms-and-when-to-get-help

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Finding blood in your poo can be alarming. Whether you notice a small streak of red on toilet paper, a darker colouration in the bowl or a persistent change in your stool appearance, it is understandable to feel concerned and want clear, reliable information.

This article draws on current NHS guidance to help you understand what blood in poo may look like, what could be causing it, and — crucially — when you need to seek medical help. It covers adults, babies, toddlers, children and people who are pregnant.

Important: If your poo is black or dark red, or if you are losing large amounts of blood, contact NHS 111 or seek urgent medical assessment straightaway. If bleeding is heavy and continuous, call 999 or go to your nearest A&E.

What Does Blood in Poo Look Like?

Blood in poo does not always look the same. The appearance depends on where in the digestive tract the bleeding is coming from and how quickly it passes through the bowel.

It is important to understand that the colour of your stool alone cannot tell you or your doctor exactly what is causing the bleeding. Only proper medical assessment can establish the cause.

When to Seek Urgent Help

NHS guidance is clear on this point, and it is worth stating early and prominently.

Call 999 or go to A&E if:

Contact NHS 111 or seek an urgent GP appointment if:

Arrange a routine GP appointment if:

Do not ignore persistent or unexplained rectal bleeding. Most causes are not life-threatening, but some require early investigation to ensure the correct treatment is given promptly.

What Causes Blood in Poo?

There are several possible causes of blood in poo, ranging from relatively common problems to conditions requiring more thorough investigation. Symptoms alone — including the appearance of blood — cannot reliably identify the underlying cause.

Haemorrhoids (Piles)

Haemorrhoids are swollen blood vessels inside or around the back passage. They are one of the most common causes of bright red blood in poo in adults. You may notice blood on toilet paper, on the surface of the stool or dripping into the toilet after passing a bowel motion. However, it is important not to assume that rectal bleeding is simply caused by piles without appropriate assessment, particularly if you are over 40, if the bleeding persists or if you have other unexplained symptoms.

Anal Fissures

An anal fissure is a small tear in the lining of the back passage. It can be caused by passing a hard stool and may cause pain alongside bright red bleeding. Fissures often improve with dietary changes and local treatment, but persistent cases require medical review.

Constipation

Straining to pass a hard or infrequent stool can cause small tears or irritation that result in bright red blood on the toilet paper or stool surface. Persistent constipation itself warrants dietary attention and, where necessary, medical advice.

Gastroenteritis and Bowel Infections

Certain bacterial infections, such as those caused by *Campylobacter*, *Salmonella* or *E. coli*, can cause bloody diarrhoea. These infections may also cause cramping, nausea and fever. Bloody diarrhoea associated with illness should be assessed promptly, particularly in young children, older adults or anyone who is immunocompromised.

Inflammatory Bowel Disease (IBD)

Conditions such as Crohn's disease and ulcerative colitis cause chronic inflammation of the bowel. Blood in poo, bloody diarrhoea, persistent abdominal pain, weight loss and fatigue are potential symptoms that may prompt investigation for IBD. A diagnosis requires specialist assessment.

Bowel Polyps

Polyps are small growths on the lining of the bowel. Many are harmless, but some can cause bleeding and may, over time, develop into bowel cancer. Most bowel polyps do not cause obvious symptoms, which is why bowel cancer screening is important.

Bowel Cancer

Blood in poo is one of the symptoms that the NHS recommends you do not ignore, as it can — in some cases — be associated with bowel cancer. This is not to suggest that most episodes of rectal bleeding indicate cancer; the majority are caused by conditions such as haemorrhoids or fissures. However, persistent or unexplained bleeding, particularly in people over 45, or bleeding accompanied by other symptoms such as unintentional weight loss, persistent changes in bowel habits or abdominal pain, should be investigated appropriately.

Other Causes

Less common causes include diverticular disease, angiodysplasia (abnormal blood vessels in the bowel wall), rectal prolapse and, in rare cases, other bowel conditions. A healthcare professional can advise on appropriate investigation based on your symptoms and medical history.

Black Stool: What Does It Mean?

Black or very dark poo has a specific significance that deserves separate attention.

Some substances can make your poo appear black without indicating a medical problem. These include:

However, black, sticky, tar-like poo — sometimes called melaena — can indicate bleeding from the stomach or upper digestive tract. When blood is digested as it travels through the gut, it turns dark before it appears in the stool. Melaena has a distinctive unpleasant smell and a sticky consistency.

Black or tarry poo that cannot be explained by iron supplements or diet should be treated as urgent. Contact NHS 111 or seek an urgent GP appointment. Do not wait to see if it resolves on its own.

Blood in Poo in Babies, Toddlers and Children

Blood in a baby's or child's poo should always be assessed by a medical professional. Children cannot reliably communicate pain or discomfort, and the causes of rectal bleeding in children differ from those in adults.

Babies

In newborns and young babies, a small amount of blood in the nappy may occasionally occur. Possible causes include:

Any blood in a baby's nappy warrants prompt medical assessment. Do not attempt to self-diagnose the cause.

Toddlers and Children

In toddlers and older children, bright red blood in poo is most commonly related to anal fissures or constipation. However, infections, allergies and, less commonly, inflammatory bowel conditions may also occur in children.

If your child has blood in their poo, contact your GP. If the child appears unwell, is in significant pain, has bloody diarrhoea or you are worried, contact NHS 111 for guidance.

Blood in Poo During Pregnancy

Rectal bleeding and vaginal bleeding are entirely different, although it is sometimes difficult for pregnant women to identify the source of bleeding. If you are unsure whether bleeding is vaginal or rectal, seek medical advice promptly.

Rectal bleeding during pregnancy is often related to:

While these causes are common and generally not dangerous to the pregnancy, persistent or unexplained rectal bleeding during pregnancy should be discussed with your midwife or GP. Do not assume that bleeding is harmless simply because pregnancy-related haemorrhoids are common.

Any bleeding during pregnancy, regardless of the suspected source, should be reported to your healthcare team so they can assess you appropriately.

Blood in Poo Samples and How Bleeding Is Investigated

When you see a GP or other healthcare professional about blood in your poo, they will typically want to understand more about your symptoms, medical history and any medications you take. They may carry out or arrange:

Clinical Assessment

A thorough history and physical examination is usually the first step. This may include an examination of the abdomen and, where appropriate, an examination of the back passage.

Stool Sample Testing

A stool sample may be requested to test for infection, inflammation or the presence of blood that is not visible to the naked eye (faecal occult blood). It is important to understand that a stool test can detect the presence of blood and some types of infection, but it cannot identify every cause of bleeding or confirm a diagnosis on its own.

Blood Tests

Blood tests can support an investigation by checking for signs of anaemia (which may result from blood loss), markers of inflammation, iron levels and other relevant indicators. A full blood count test can identify whether blood loss has led to a reduction in red blood cells or haemoglobin levels — useful information for a healthcare professional assessing possible rectal bleeding. However, a blood test cannot identify where bleeding is occurring or confirm its cause.

For those considering a broader health assessment alongside bowel symptom investigations, health screening packages can provide additional information about general health markers, though they are not a substitute for medical assessment of bowel symptoms.

Further Investigations

Depending on your symptoms, examination findings and initial test results, a GP may refer you for further investigation. This may include:

The investigations recommended will depend on your individual clinical picture. A private blood test or stool sample alone cannot rule out bowel cancer or any other serious bowel condition. Appropriate clinical assessment is essential.

What Happens After Medical Assessment?

Following assessment, the next steps depend on what is found during examination, initial tests and your medical history. Your GP or hospital team will advise on the most appropriate course of action.

Some people will be given dietary advice, topical treatments or reassurance following a clear examination. Others will be referred for specialist assessment or further investigations. The important thing is not to delay seeking advice, particularly if bleeding persists, changes in character or is accompanied by other symptoms.

If you are waiting for NHS investigations and would like to check general health markers in the meantime, Private Blood Tests London offers a range of private blood tests that can be arranged quickly and without a GP referral. These may provide useful background information for you or your doctor, but they should always complement — not replace — appropriate medical assessment and any NHS-recommended investigations.

Frequently Asked Questions

What should I do if I notice blood in my poo?

Do not ignore it. If the poo is black or dark red, contact NHS 111 or seek an urgent GP appointment. If you are losing a large amount of blood or feel faint, call 999 or go to A&E. For small amounts of bright red blood that have persisted for more than a few days, arrange a routine GP appointment.

What causes bright red blood in poo?

Bright red blood typically suggests bleeding from the lower digestive tract. Common causes include haemorrhoids, anal fissures and constipation-related injury. However, the appearance of blood alone cannot confirm the cause, and persistent bleeding should be assessed by a GP.

What does black poo mean?

Black poo can be caused by iron supplements, certain foods or medications. However, black, sticky, tar-like stools (melaena) can indicate bleeding from the stomach or upper digestive tract. If you cannot attribute the colour to supplements or diet, contact NHS 111 or seek urgent medical advice.

When should I worry about blood in my stool?

Seek urgent help if stools are black or very dark red, if bleeding is heavy or continuous, or if you feel faint or unwell. Seek routine GP advice if bright red blood persists beyond a few days, if bowel habits change unexpectedly or if you have any ongoing concerns.

Is blood in poo always serious?

Not always, but it should never be dismissed without appropriate assessment. Many causes are common and treatable, but some require early investigation. Persistent or unexplained rectal bleeding always warrants medical review.

What should I do if my child has blood in their poo?

Contact your GP. If your child appears unwell, is in significant pain, has bloody diarrhoea or you are worried, contact NHS 111 for guidance. Do not attempt to identify the cause yourself.

Why might a baby have blood in their poo?

Possible causes in babies include milk protein allergy, anal fissures, constipation or, rarely, more serious bowel conditions. Any blood in a baby's nappy should be assessed by a healthcare professional promptly.

What causes blood in poo during pregnancy?

Common causes include haemorrhoids and anal fissures, both of which are more frequent during pregnancy. However, persistent or unexplained rectal bleeding during pregnancy should be discussed with your midwife or GP and not assumed to be harmless.

Can a stool sample detect blood in poo?

Yes. A faecal occult blood test can detect blood that is not visible to the naked eye. Stool samples can also test for infection and inflammation. However, a stool test alone cannot identify every cause of bleeding or provide a diagnosis without further clinical assessment.

What blood tests might be needed for blood in poo?

A full blood count is commonly used to check for anaemia, which may develop as a result of rectal bleeding. Inflammatory markers, iron studies and other tests may also be requested depending on the clinical picture. Blood tests support an investigation but cannot identify the source or cause of bleeding on their own.

Can blood in poo be caused by what I eat?

Certain foods can change stool colour. Beetroot can cause red or pink stools; blueberries or liquorice may cause darker stools; iron-rich foods or iron supplements can cause black or very dark stools. If you cannot confidently attribute a change to diet and colour persists, seek medical advice.

Does blood in poo always mean bowel cancer?

No. The majority of rectal bleeding episodes are caused by common conditions such as haemorrhoids, fissures or infections. However, blood in poo is a symptom that the NHS recommends you do not ignore, as it can in some cases be associated with bowel cancer. Early investigation is the safest approach, particularly if bleeding is persistent, unexplained or accompanied by other symptoms such as weight loss or changes in bowel habit.

This article is intended for educational purposes only and does not constitute medical advice, diagnosis or treatment. Always consult a qualified healthcare professional about your symptoms. In an emergency, call 999. For urgent non-emergency advice, contact NHS 111.

Information is based on current NHS guidance available at the time of publication. Medical recommendations may change; always refer to the latest NHS and NICE guidance for up-to-date advice.