Blood in Stool: Common Causes and When You Should See a Doctor

What Does Blood in Stool Mean?

Seeing blood in stool can be concerning. While there are many possible explanations, the symptom should not simply be ignored or automatically attributed to hemorrhoids.

Blood may originate from different areas of the gastrointestinal tract, including the stomach, small intestine, colon, rectum, or anus.

Depending on where the bleeding originates, you might notice:

The appearance of the blood can provide clues about its source, but it cannot confirm the underlying condition.

If bleeding persists or repeatedly returns, identifying its cause is important.

What Are the Most Common Causes of Blood in Stool?

Many conditions can cause gastrointestinal or rectal bleeding.

Some are minor and relatively easy to treat. Others require further diagnostic testing or specialized colorectal care.

Potential causes include:

Understanding the differences between these conditions can help explain why a proper evaluation may be necessary.

1. Hemorrhoids

Hemorrhoids are swollen veins located around the anus or inside the lower rectum.

They are a common cause of bright red rectal bleeding.

Blood from hemorrhoids may appear:

• On toilet paper
• On the outside of stool
• In the toilet after a bowel movement

Internal hemorrhoids can bleed without causing substantial pain. External hemorrhoids may cause discomfort, swelling, irritation, or itching.

Constipation and repeated straining during bowel movements can increase pressure on the veins around the rectum and contribute to hemorrhoid development.

Although hemorrhoids are common, other colorectal conditions can cause similar bleeding. Recurring symptoms should therefore be evaluated rather than automatically assumed to be hemorrhoids.

2. Anal Fissures

An anal fissure is a small tear in the tissue lining the anus.

Fissures commonly develop after passing a large or hard stool and are frequently associated with constipation.

Symptoms can include:

• Bright red blood on toilet paper
• Blood on the outside of stool
• Sharp pain during bowel movements
• Burning after a bowel movement
• A visible tear around the anus

Pain during or immediately after a bowel movement is particularly common with anal fissures.

Some fissures heal with conservative measures, while chronic fissures may require additional treatment.

3. Constipation

Constipation can contribute indirectly to rectal bleeding.

Hard stools may irritate or damage delicate tissue around the anus. Repeated straining also increases the likelihood of developing hemorrhoids or anal fissures.

People experiencing constipation may benefit from improving fiber intake, drinking adequate fluids, remaining physically active, and developing healthier bowel habits.

Persistent constipation may require additional evaluation to identify an underlying cause.

4. Diverticular Disease

Diverticula are small pouches that can form along weakened areas of the colon wall.

Having these pouches is known as diverticulosis. Inflammation or infection of one or more pouches results in diverticulitis.

Diverticular bleeding can sometimes produce a noticeable amount of blood without significant pain.

Diverticulitis may instead cause symptoms such as:

• Abdominal pain
• Fever
• Changes in bowel habits
• Nausea
• Abdominal tenderness

Significant bleeding, persistent abdominal pain, or other symptoms associated with diverticular disease should be evaluated by a healthcare professional.

5. Colon Polyps

Colon polyps are growths that form along the inner lining of the colon or rectum.

Most polyps do not cause symptoms. However, some can bleed.

This bleeding may be visible, or it may occur in such small amounts that it cannot be seen without testing.

Over time, chronic blood loss can potentially contribute to iron deficiency anemia.

Certain types of colon polyps can also become cancerous. Detecting and removing precancerous polyps is one of the primary reasons colorectal cancer screening is so important.

6. Inflammatory Bowel Disease

Inflammatory bowel disease, or IBD, includes Crohn’s disease and ulcerative colitis.

These chronic conditions cause inflammation within the gastrointestinal tract.

Depending on the type and severity of IBD, symptoms can include:

• Blood in the stool
• Bloody diarrhea
• Abdominal pain
• Frequent bowel movements
• Bowel urgency
• Fatigue
• Unexplained weight loss

Persistent bloody diarrhea or bleeding accompanied by abdominal pain should be evaluated.

7. Colorectal Cancer

Blood in the stool can sometimes be a symptom of colorectal cancer.

This does not mean that everyone who notices rectal bleeding has cancer. Hemorrhoids, fissures, diverticular disease, and other benign conditions are also common causes.

However, unexplained or persistent bleeding should not be ignored.

Other potential colorectal cancer symptoms can include:

• Persistent changes in bowel habits
• Unexplained weight loss
• Abdominal discomfort
• Changes in stool shape or consistency
• Fatigue
• Iron deficiency anemia
• A feeling that the bowel does not completely empty

The presence of these symptoms does not confirm cancer, but they are reasons to discuss further evaluation with a healthcare professional.

What Does the Color of Blood in Stool Mean?

The appearance of blood can sometimes provide information about where the bleeding may be occurring.

What Does Bright Red Blood When Wiping Mean?

Finding bright red blood on toilet paper after a bowel movement is relatively common.

Hemorrhoids and anal fissures are frequent causes, particularly when bleeding occurs after constipation or straining.

However, bleeding should be evaluated if it:

• Happens repeatedly
• Increases in amount
• Occurs without constipation
• Is mixed into the stool
• Appears with abdominal pain
• Is accompanied by a change in bowel habits
• Occurs with unexplained weight loss or fatigue

The amount of visible blood alone does not determine how serious the underlying cause may be.

Can You Have Blood in Stool Without Seeing It?

Yes.

Occult gastrointestinal bleeding occurs when the amount of blood is too small to be seen with the naked eye.

This type of bleeding may continue gradually over time.

Chronic blood loss can contribute to iron deficiency anemia, which may cause:

• Fatigue
• Weakness
• Pale skin
• Shortness of breath
• Dizziness

Blood and stool testing may help identify bleeding that is not otherwise visible.

When Should You Worry About Blood in Stool?

Persistent or recurrent blood in stool deserves medical attention even when the amount appears small.

Consider contacting a healthcare professional when bleeding:

Personal and family medical history also matter.

Someone with a personal history of colon polyps, inflammatory bowel disease, colorectal cancer, or a significant family history may require a different level of evaluation than someone without these risk factors.

When Is Rectal Bleeding an Emergency?

Some gastrointestinal bleeding requires immediate medical attention.

Seek emergency care for symptoms such as:

Significant gastrointestinal bleeding can result in dangerous blood loss and should not wait for a routine medical appointment.

How Do Doctors Diagnose the Cause of Blood in Stool?

Evaluation typically begins with a discussion of your symptoms and medical history.

A physician may ask:

• What color is the blood?
• How much blood are you seeing?
• Is the blood on the toilet paper, outside the stool, or mixed into it?
• When did the bleeding begin?
• Does it occur with every bowel movement?
• Are bowel movements painful?
• Have your bowel habits recently changed?
• Have you experienced abdominal pain?
• Have you lost weight unexpectedly?
• Do you have a family history of colorectal cancer or polyps?

A physical examination may also be performed.

Depending on your symptoms and risk factors, further testing may include:

The appropriate diagnostic approach depends on the suspected source of bleeding.

Why Might a Colonoscopy Be Recommended?

Colonoscopy allows a physician to examine the lining of the rectum and entire colon.

During the procedure, abnormalities such as the following may be identified:

• Colon polyps
• Areas of inflammation
• Diverticular disease
• Sources of bleeding
• Suspicious growths
• Colorectal tumors

Polyps can often be removed during the same procedure and sent to a laboratory for analysis.

Regular colorectal cancer screening is also important because colorectal cancer and precancerous polyps may develop without obvious symptoms.

However, routine screening and diagnostic evaluation are not necessarily the same thing. A patient experiencing rectal bleeding may require evaluation even if they are not currently due for routine screening.

How Is Blood in Stool Treated?

There is no single treatment for rectal bleeding because treatment depends on the underlying cause.

Hemorrhoids

Treatment may include:

• Increased dietary fiber
• Improved hydration
• Changes in bowel habits
• Medication
• Office-based procedures
• Surgery for more advanced cases

Anal Fissures

Treatment may involve:

• Stool softening
• Increased fiber
• Adequate hydration
• Topical medications
• Procedures for chronic fissures

Diverticular Disease

Treatment depends on whether bleeding, inflammation, infection, or another complication is present.

Inflammatory Bowel Disease

IBD generally requires ongoing medical management designed to reduce inflammation and control symptoms.

Colon Polyps

Polyps are often removed during colonoscopy.

Colorectal Cancer

Treatment varies depending on the location and stage of the cancer and may include surgery, chemotherapy, radiation therapy, or a combination of treatments.

The important point is that treating rectal bleeding effectively requires determining why the bleeding is occurring.

Can Blood in Stool Be Prevented?

Not every cause of gastrointestinal bleeding can be prevented.

However, healthy bowel habits may reduce the risk of certain conditions associated with rectal bleeding.

Eat Enough Fiber

Fiber can help produce softer, easier-to-pass stools.

Good sources include:

• Fruits
• Vegetables
• Whole grains
• Beans
• Lentils

Drink Enough Fluids

Adequate hydration can help reduce hard stools and constipation.

Avoid Excessive Straining

Repeated straining during bowel movements can contribute to hemorrhoids and anal fissures.

Stay Physically Active

Regular physical activity can support healthy bowel function.

Do Not Ignore Persistent Symptoms

Rectal bleeding, persistent changes in bowel habits, unexplained abdominal symptoms, and unusual fatigue should be discussed with a healthcare professional.

Keep Up With Recommended Colorectal Screening

Routine screening can identify precancerous polyps and colorectal cancer before obvious symptoms develop.

Seeing blood in stool can be unsettling, but there are many possible explanations. Hemorrhoids and anal fissures are common causes, while diverticular disease, inflammatory bowel disease, colon polyps, and colorectal cancer can also produce gastrointestinal bleeding.

The most important step is determining why the bleeding is occurring rather than trying to diagnose the cause based solely on its appearance.

Persistent, recurring, or unexplained rectal bleeding should be medically evaluated. Early diagnosis can provide reassurance when the cause is minor and allow appropriate treatment when a more significant colorectal condition is present.