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Blood in Stool (Faeces): Causes, Diagnosis, and Treatment

Blood in stool indicates an underlying medical condition that ranges from mild to severe. Learn more about its causes and when to seek medical attention.

Health Screening

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Published on 31 Mar 2025

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By Thomson Team

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Why is there blood in my stool?

After using the toilet, you may feel alarmed if you notice blood in your stool (faeces). It's understandable to feel this way, as the presence of blood in the stool is not normal and may indicate bleeds somewhere in the digestive tract.

But this condition isn't always a cause for concern, because simply straining too hard during constipation can cause blood in your stool too. However, if you experience heavy bleeding during defecation, especially when accompanied by abdominal pain, it may indicate an underlying health problem that requires medical attention.

What does blood in stool mean? 

Blood in your stool can appear in different forms, such as streaks of blood on your faeces, blood clots, or blood mixed with mucus. The source of this blood can come from various locations, including the stomach, small intestine (duodenum), and large intestine (colon), or anus, all of which are part of the digestive tract.

blood in poop colour

The appearance of blood in your stool can vary depending on its source, which includes:

  • Bright red blood in stool

    • If you notice bright red blood on the toilet paper after wiping or in the toilet bowl, it may indicate bleeding from the lower gastrointestinal tract, such as the lower colon, rectum, or anus (also known as rectal bleeding).

  • Dark red or maroon blood

    • If your stool appears dark red or maroon, it may indicate bleeding in the upper part of your large intestine.

  • Black blood

    • If you're experiencing black blood in your stools (also known as melena), it means that the blood from the bleeding site has been digested, indicating bleeding in the upper part of the gastrointestinal tract, such as the stomach or the small intestine.

When should I worry about blood in stools?

While blood in your faeces doesn't always mean you have a serious condition, you should seek immediate medical attention if you experience any of the following:

  • Heavy bleeding during defecation.

  • Severe abdominal pain alongside dark, tarry stools.

  • Prolonged bleeding during defecation along with changes in the frequency or consistency of bowel movements for more than 3 weeks.

  • Blood in stools accompanied by a fever, vomiting, dizziness, chills, fainting, or weakness.

If you notice blood in your stools, it's important to keep a record of your stool conditions. Document when you first noticed the blood, the amount and colour of it, and any accompanying symptoms, as these details will aid your healthcare provider in making a diagnosis.

If you are experiencing any of these symptoms, request an appointment with Thomson Medical. Our specialists can assist with further diagnosis to identify the cause of blood in your stool and provide an appropriate treatment plan.

Causes of blood in stool

If there's blood in your stool, it’s a sign that there’s bleeding happening somewhere in your digestive system. It could be either an early symptom of a medical condition or caused by an existing medical condition.

Here are some common medical conditions that could lead to blood in stool, including:

  • Haemorrhoids

    • This condition occurs when there are swollen veins in the lower rectum or anus. These blood vessels can protrude near the anal canal, and if you strain too hard during defecation or suffer from constipation, they may rupture and cause rectal bleeding.

  • Anal fissures

    • An anal fissure is a tear in the lining of the anal canal, the passage through which stool exits the body. This condition often occurs due to excessive straining during bowel movements, particularly when dealing with constipation or passing large stools.

  • Inflammatory bowel disease (IBD)

    • Inflammatory bowel disease refers to diseases that cause inflammation and swelling in the gastrointestinal (GI) tract. The most common types of IBD are Crohn’s disease and ulcerative colitis.

  • Diverticulitis

    • This condition occurs when small pouches in the inner lining of your colon, known as diverticula, get infected and inflamed. Diverticulitis can make the blood vessels inside the diverticula more fragile and easily ruptured.

  • Sexually transmitted infections (STIs)

    • Some sexually transmitted infections (STIs), such as gonorrhoea, chlamydia, and syphilis, can cause inflammation and bleeding in the anal or rectal lining. Additionally, STIs like herpes may cause the development of sores within the rectum that could bleed.

  • Stomach ulcer

    • A stomach ulcer occurs when the protective stomach lining is irritated, causing an open sore. This condition is commonly an infection from the bacteria Helicobacter pylori (H. pylori) or consuming non-steroidal anti-inflammatory drugs (NSAIDs).

  • Infections

    • Some bacterial infections, such as E. coli and Salmonella, can cause haemorrhagic colitis, or bleeding from your digestive tract. The condition usually manifests as bloody diarrhoea.

  • Colon polyps and colorectal cancer

    • A colon polyp is a non-cancerous growth in the lining of the colon or rectum that can cause bleeding. This growth can also develop into colorectal cancer over time and is more likely to bleed.

Blood in stool in children

In addition to adults, children can also experience blood in their stool. Here are some common causes of this condition in children, such as:

  • Constipation

    • Constipation is characterised by hard, dry stools, which can make bowel movements uncomfortable. When your children strain too hard while defecating, it can cause anal fissures that lead to blood in their faeces.

  • Food allergies

    • Some food sensitivities or allergies, such as to milk, fish, or eggs, can trigger colitis, an inflammation of the large intestine (colon) in children. This inflammation can cause swelling and irritation, leading to blood in the stool.

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Diagnosing blood in stool

To diagnose the source of the blood in your faeces, your healthcare provider will start the assessment by asking about the colour of your stool, whether there are other symptoms you're experiencing, and when you first noticed the bleeding.

After that, they may also check your medical history and perform a rectal examination. This examination can help the healthcare provider to assess the condition of the anus and rectum, which can help identify common causes of blood in stool, such as haemorrhoids or anal fissures.

If the cause of the bleeding isn’t immediately apparent, further diagnostics may be necessary, which can include:

  • Stool tests

    • This diagnostic test analyses stool samples for signs of active bleeding, infection, or inflammation that could be causing blood in the stool.

  • Minimally invasive examination

    • These procedures use a thin, flexible tube equipped with a small camera and light, which is inserted into the body in different places. 

    • During this procedure, if any abnormal growth (polyps) is found, it can be removed and tested for cancer. There are 3 minimally invasive diagnostics that are commonly performed, such as:

      • Colonoscopy: A flexible tube is inserted through the anal canal. This exam allows a detailed view of the rectum, the entire colon, and parts of the small intestine.

      • Endoscopy: A tube is inserted through the throat to examine the upper digestive tract, such as the oesophagus, stomach and upper part of the small intestine.

      • Enteroscopy: Similar to an endoscopy, allows the healthcare provider to examine the entire small intestine, reaching deeper than an endoscopy can.

  • Rectal culture swab

    • This diagnostic procedure entails collecting a sample from your rectum, which is then sent to a laboratory for analysis. The lab will examine the sample to identify any bacteria that are causing an infection.

  • Imaging test

    • Imaging tests, such as CT angiography (a specialised type of CT scan), can help identify the cause and source of the bleeding. During this procedure, a contrast dye is injected into a vein. This dye makes the blood vessel more visible, highlighting the areas where the bleeding happened.

To accurately diagnose what's causing the blood in the faeces, request an appointment at Thomson Medical. Our specialists will assist you throughout the diagnosis and treatment processes and provide personalised advice.

Treatment for blood in stool

Blood in stool can be caused by various conditions, ranging from mild to severe, so there is no one-size-fits-all treatment available. Therefore, your healthcare providers will focus on treating the specific condition causing the bleeding. Depending on the diagnosis, treatment options may include:

1) Dietary changes

  • Constipation

    • If constipation is the cause of rectal bleeding, you need to change your diet by eating more fruits, vegetables, and whole grains and drinking enough water daily. This approach can help soften stools and minimise straining.

  • Diverticulitis

    • To treat diverticulitis, your healthcare provider may recommend dietary changes, starting with a liquid diet. As your condition improves, you can gradually eat more low-fibre solid foods. Once fully recovered, you can resume your regular diet and eat more high-fibre foods to prevent future flare-ups.

  • Food allergy

    • A food allergy may result in blood in the stool for children. In such cases, the recommended treatment includes removing the allergenic foods from their diet.

2) Medications administered

  • Infections

    • Your healthcare provider might prescribe antibiotics, like amoxicillin, to treat gastrointestinal bleeding caused by bacterial infections, such as stomach ulcers (which is caused by bacterium H. pylori.)

  • Inflammatory bowel disease

    • To treat this condition, anti-inflammatory drugs (such as mesalamine) or immunosuppressants are used to manage swelling and inflammation from Crohn's disease or ulcerative colitis.

  • Sexually transmitted infections (STIs)

    • The medications for STIs that cause blood in stool will vary depending on the specific infection. Your healthcare provider will do a diagnosis of your medical conditions first to determine the appropriate medications for you.

3) Topical treatments

  • To manage conditions such as anal fissures and haemorrhoids, your healthcare provider may provide corticosteroid creams or other topical creams to help reduce pain and swelling.

4) Surgical procedure

Surgery may be necessary to treat severe cases of gastrointestinal bleeding when other conservative treatments are ineffective. Here are some conditions that may require surgical interventions, including:

  • Haemorrhoids

    • For severe or recurrent haemorrhoids that don't respond to conservative treatments like topical cream, a haemorrhoidectomy (surgical removal of haemorrhoidal tissue) can be performed.

  • Colon polyps or cancer

    • Surgical intervention may be required if colon polyps are too large to be removed during colonoscopy. As for patients with colorectal cancer, surgery is the preferred treatment option to ensure complete removal and prevent further spread of cancer cells.

FAQ

What is the reason for blood in the stool?

Numerous medical conditions, including the following, can cause blood in your stools.

  • Haemorrhoids

  • Anal fissures

  • Inflammatory bowel disease

  • Infections

  • Colorectal cancer

  • Stomach ulcers

  • Constipation

Is it serious if you poop blood?

Seeing blood, blood clots, or even bloody mucus in your stool can be concerning, but it isn't always an indication of a serious health issue. It depends on the amount of bleeding, the colour of the blood, and the underlying medical condition that causes it.

What should I eat if I have blood in my stool?

If you notice blood in your stool, it could be caused by constipation, which makes you strain too hard during bowel movements. To help soften stools and minimise straining, change your diet by eating more fruits, vegetables and whole grains while ensuring you’re drinking enough water daily.

Why am I pooping blood with no pain?

If you notice bright red blood in your stool but aren’t experiencing any pain, it could be due to something mild, like haemorrhoids or an anal fissure. To help treat these conditions, you can apply corticosteroid cream to the affected area. However, if the conditions continued for a prolonged time, consult your healthcare provider. 

What does cancerous bloody stool look like?

Bloody stools from cancer often appear dark and tarry (melena) because the blood is digested as it moves through the digestive tract. If this type of stool occurs along with other symptoms such as unexplained weight loss, fatigue, or changes in bowel habits, it is essential to consult a healthcare professional.

The information provided is intended for general guidance only and should not be considered medical advice. For personalised recommendations based on your medical conditions, request an appointment with Thomson Medical.

For more information, contact us:

Thomson Specialists Paragon (Health Screening)

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