Rectal bleeding is often caused by minor conditions such as haemorrhoids or anal fissures and may settle on its own. However, in some cases, it can be a sign of underlying issues within the bowel that require further evaluation.

Medical assessment is recommended when rectal bleeding is persistent, recurrent or accompanied by symptoms such as changes in bowel habits, abdominal pain or unexplained weight loss. The key concern is whether there is an underlying condition that is unlikely to resolve without proper investigation and targeted treatment.

Key Takeaways

Rectal bleeding can range from minor causes such as haemorrhoids to more serious conditions including bowel disease or cancer
Even small or occasional bleeding should not be ignored if it keeps recurring
Symptoms like weight loss, persistent change in bowel habits or abdominal pain increase concern
Early assessment helps identify the cause and ensures appropriate treatment is started

Man holding toilet paper with visible blood suggesting rectal bleeding.

What is Rectal Bleeding?

Rectal bleeding refers to blood being passed from the back passage, either seen on toilet paper, in the toilet bowl or mixed with stool. It can appear bright red, dark red or occasionally black depending on where the bleeding originates in the digestive tract.

While it is often linked to benign conditions, it is not a symptom to dismiss without understanding the cause. The underlying reason can only be confirmed through proper medical assessment by a colorectal specialist, especially if the bleeding persists or occurs alongside other symptoms.

Common Causes of Rectal Bleeding

Rectal bleeding can arise from a range of conditions affecting the anus, rectum or lower bowel, with causes ranging from mild irritation to more significant underlying disease.

Haemorrhoids

Haemorrhoids are swollen blood vessels in the rectum or anus and are one of the most common causes of rectal bleeding. The blood is usually bright red and noticed after wiping or on the surface of stools. They may be associated with itching, discomfort or a feeling of fullness.

Anal Fissures

Anal fissures are small tears in the lining of the anus, often caused by constipation or straining. They typically cause sharp pain during bowel movements alongside small amounts of fresh bleeding.

Diverticular Disease

Diverticular disease occurs when small pouches form in the colon wall. These can occasionally bleed or become inflamed, sometimes leading to sudden or noticeable rectal bleeding.

Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, causes chronic inflammation in the bowel. This may lead to recurring diarrhoea, abdominal pain and blood in the stool.

Polyps and Colorectal Cancer

Polyps are growths in the bowel that may bleed intermittently. While many are harmless, some can develop into colorectal cancer over time. Bleeding may be subtle and accompanied by changes in bowel habits.

When Should Rectal Bleeding Be Taken Seriously?

Here are some signs that rectal bleeding may be more serious and should be assessed by a colorectal specialist without delay.

Heavy or ongoing bleeding that does not stop
Presence of clots or large amounts of blood
Black or tarry stools which may suggest higher gastrointestinal bleeding
Dizziness, fainting or weakness that may indicate significant blood loss
Persistent changes in bowel habits such as diarrhoea or constipation
Narrower stools or a noticeable change in stool shape
Abdominal pain, fever or unexplained weight loss occurring alongside bleeding

Woman sitting and holding her abdomen in discomfort, indicating abdominal pain.

How Is Rectal Bleeding Investigated?

Clinical Assessment

A doctor will begin with a detailed history and physical examination to understand the nature of the bleeding and any associated symptoms.

Diagnostic Tests

Depending on the findings, further tests may include blood tests, stool tests and imaging or endoscopic procedures such as a colonoscopy.

Role of Colonoscopy

A colonoscopy allows direct visual examination of the bowel and is one of the most effective ways to identify the source of rectal bleeding and rule out serious conditions.

Take the Next Step in Understanding Your Symptoms

Rectal bleeding is often due to benign conditions, but it can also be an early sign of more significant bowel disease. The challenge lies in distinguishing between the two, which is why timely assessment is important.

At Thesurgeons, a colorectal clinic in Singapore, patients receive comprehensive assessment and personalised care for symptoms such as rectal bleeding, bowel habit changes and other digestive concerns. Care is led by Dr Chew Min Hoe, an experienced colorectal specialist with expertise in colonoscopy and the diagnosis of colorectal conditions. If you are experiencing persistent or unexplained rectal bleeding, schedule a consultation for a thorough assessment and greater peace of mind today.

Meet Our Colorectal Specialist in Singapore

Dr Chew Min HoeMedical DirectorSenior Consultant, General & Colorectal SurgeonMBBS (Singapore), MRCS (Edinburgh), MMed (Surgery), FRCS (Edinburgh)

Dr Chew Min Hoe has devoted over 25 years of service to the public sector and was the founding Head of the Department of Surgery at Sengkang General Hospital (SKH). His clinical speciality is General and Colorectal Surgery with special niche interests in colorectal cancer, advanced pelvic tumours, hereditary conditions as well as perianal surgery. He is highly involved in education and research, and has published more than 100 peer-reviewed articles.

Rectal Bleeding: What Causes It and When Should I Worry?