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

If you’ve noticed blood in your stool, it’s normal to feel anxious or unsure. It can happen for many reasons, some minor, like constipation or piles, and others that may need a closer look. It’s not always easy to tell what’s serious, especially when it comes to something as personal as bathroom habits. But it’s more common than you might think.

Knowing what to watch for, from colour to frequency, can help you feel more in control. And if something doesn’t feel right, talking to a doctor can bring clarity and peace of mind.

Why is there blood in your stool?

The colour of the blood in your stool can tell you a lot about where it's coming from. Sometimes, it’s linked to minor issues like piles or a small tear. But in some cases, it could point to something deeper in your digestive system.

Here are what different blood colours often mean:

• Bright red blood:

  • This colour usually means the bleeding occurred in the lower part of the digestive tract, near the anus.

  • This includes the rectum or near the anus, or the lower portion of the colon. It might show up on toilet paper or in the bowl. Common causes include piles (haemorrhoids) or anal fissures.

• Dark red or maroon blood:

  • If your faeces are dark red or maroon, it usually means there's been bleeding higher up in your large intestine or maybe even in your small intestine. It’s a sign the blood has been inside a bit longer before coming out.

• Black or tar-like stool (melena):

  • This colour often indicates bleeding in the stomach or upper small intestine, where the blood has been digested. A common cause is a stomach ulcer.

If you’re not sure what’s causing the bleeding or if it keeps happening, it’s best to be examined by a doctor. They can help diagnose the cause and recommend the next steps.

What causes blood in your 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 is a type of peptic ulcer that occurs when the protective stomach lining is irritated, causing an open sore.

  • This condition is commonly caused by an infection from the bacteria Helicobacter pylori (H. pylori) or by consuming non-steroidal anti-inflammatory drugs (NSAIDs).

• Ischaemic colitis:

  • This is a condition where the blood supply to the large intestine or colon is either disrupted or reduced temporarily. This can cause tissue damage and bleeding.

• Anal fistula:

  • An anal fistula is a small tunnel that develops from inside the anus (the end of the large intestine) to the skin on the outer side. The problem usually begins with the anal glands, where infections can form. These infections can cause rectal bleeding.

• 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.

When should you visit a doctor?

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.

You may also find it helpful to reference the Bristol stool chart to describe the consistency and type of your stool, 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.

How to diagnose the source of 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 any 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

These diagnostic tests analyse stool samples for signs of active bleeding, infection or inflammation that could cause blood in the stool.

But since rectal bleeding isn’t always visible to the naked eye and can only be seen under a microscope (occult bleeding), your doctor may also perform a faecal occult blood test (FOBT) to detect tiny traces of bleeding.

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: 

  • During this procedure, a flexible tube is inserted through the anal canal. This examination provides a detailed view of the rectum, the entire colon, and parts of the small intestine.

• Endoscopy: 

  • An endoscopy involves inserting a tube through the throat to examine the upper digestive tract, including the oesophagus, stomach, and the upper part of the small intestine.

• Enteroscopy:

  • This procedure is similar to an endoscopy and allows the healthcare provider to examine the entire small intestine.

Rectal culture swab

To diagnose blood in your stool, your doctor may perform a rectal swab culture, collecting a sample from your rectum to send to a laboratory for analysis. The laboratory will examine the sample to identify any bacteria causing an infection.

Imaging test

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

Additionally, a magnetic resonance enterography (MRE), which is an MRI scan focused on the small intestine, may also be performed to diagnose and monitor IBD such as Crohn's disease.

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

Blood in stool diagnosis at Thomson Medical

Dealing with blood in your stool can be worrying because the cause of the condition isn't always obvious. At Thomson Medical, our gastroenterology specialists provide thorough care, from diagnosis to treatment and follow-up support. We can help you with:

• Diagnostic procedures, including colonoscopy and endoscopy

• Clear explanations of your results and treatment options

• Ongoing monitoring and follow-up care tailored to your needs

The cost of a colonoscopy at private hospitals in Singapore ranges from SGD 2,800 to SGD 9,610 for day surgery and from SGD 2,600 to SGD 19,200 for inpatient surgery, depending on the complexity of the procedure. Additional costs may apply for pre-consultations, imaging tests, medications, and follow-up appointments.

For further information about costs and payment options for treatment at Thomson Medical, please contact our medical concierge team.

How is blood in stool treated?

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:

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 soften stools and minimise strain.

• 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.

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.

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.

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?

Is it serious if you notice blood in your stool?

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 strain, 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 continue 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.

Can stress cause blood in the stool?

Why do children have blood in their stool?

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.