What Causes Bowel Leakage in Adults? 6 Common Reasons

Bowel leakage may show up as a small stain, an accident you could not prevent or stool passing without you feeling it happen. It can lead to extra planning, such as checking for restrooms before going out or carrying a change of clothes.

Also called accidental bowel leakage or fecal incontinence, this problem can have several causes. Loose stools, constipation, weakened muscles, nerve changes, medical treatments and difficulty reaching the bathroom can all play a role. In many cases, more than one factor is involved.^1,3

This guide explains six common causes of bowel leakage, when to talk with a healthcare provider and which management options may be available.

What Is Bowel Leakage?

Bowel leakage is the accidental passage of solid or liquid stool. It may also include mucus or staining in your underwear. Some people experience a sudden urge but cannot reach a bathroom in time. Others pass stool without realizing it is happening.^1,3

You may hear bowel leakage called:

• Accidental bowel leakage, or ABL
• Bowel incontinence
• Fecal incontinence, or FI
• Loss of bowel control

These terms generally describe the same bowel-control problem.

Symptoms do not look the same for everyone. Some people notice an occasional stain in their underwear. Others have more frequent accidents that disrupt work, sleep, exercise or social activities. Leakage may happen without warning, or it may follow an urgent need to use the bathroom.

What Causes Bowel Leakage in Adults?

The most common causes of bowel leakage include diarrhea, constipation, muscle or nerve changes, mobility limitations, medical treatments and health conditions that affect digestion or bowel control. More than one of these factors may be present at the same time.^1,3

1. Chronic Diarrhea or Loose Stools

Loose or watery stool fills the rectum quickly and is harder to hold than formed stool. Even someone with strong pelvic floor muscles may have difficulty controlling liquid stool, especially when the urge to use the bathroom comes on suddenly.

Possible causes of chronic loose stools include:

• Irritable bowel syndrome (IBS), particularly IBS with diarrhea
• Inflammatory bowel diseases such as Crohn’s disease or ulcerative colitis
• Celiac disease
• Bile acid malabsorption
• Foods or ingredients that worsen diarrhea for you, which may include lactose, certain artificial sweeteners or high-FODMAP foods
• Medications such as some antibiotics, magnesium-containing antacids and diabetes medications
• Gastrointestinal infections^1,4

If loose or watery stools have become a regular part of your week, mention that pattern to your healthcare provider. A stool or food diary may help you track when symptoms happen and whether certain foods, medications or routines seem connected.

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) recommends discussing dietary changes with a healthcare professional because the appropriate approach depends on whether diarrhea, constipation or another condition is contributing.²

2. Constipation and Overflow Leakage

Constipation may seem like the opposite of bowel leakage, but the two can occur together.

When hard stool collects in the rectum, softer or more liquid stool may build up behind it and leak around the blockage. This is sometimes called overflow leakage. Over time, large, hard stools can also stretch and weaken the muscles in the rectum.^1,3

Possible signs of constipation-related leakage include:

• Feeling as though you cannot completely empty your bowels
• Passing small, hard stools
• Straining during bowel movements
• Going several days without a bowel movement
• Noticing staining or watery leakage despite feeling constipated^1,3

3. Muscle or Nerve Changes

Bowel control depends on the muscles of the pelvic floor, anus and rectum working together. It also depends on nerves that help you feel when the rectum is full and tell the appropriate muscles when to tighten or relax.¹

If these muscles become weak or injured—or the nerves cannot send signals properly—it may become harder to recognize or control a bowel movement.

Possible contributors include:

• Age-related changes: Muscles may gradually lose strength over time, including those involved in bowel control.
• Childbirth-related injury: Vaginal deliveries, especially those involving tearing, forceps, or a large baby, can affect the pelvic floor muscles or nerves—sometimes without symptoms showing up until years later.
• Pelvic or colorectal surgery: Procedures involving the anus, rectum or nearby structures may affect muscles, nerves or sensation.
• Neurological conditions: Multiple sclerosis (MS), Parkinson’s disease, stroke, spinal cord injury and certain brain injuries may disrupt communication between the brain and bowel.
• Diabetes-related nerve damage: Neuropathy can reduce rectal sensation, making it harder to recognize when a bowel movement is coming.
• Repeated straining: Long-term straining during bowel movements may damage the nerves that support bowel control.^1,3

These changes do not automatically mean that bowel leakage is permanent. An evaluation can help determine whether treatment or symptom-management options may help.

4. Mobility Limitations

Sometimes the bowel-control system is working, but a person cannot reach or use the bathroom quickly enough. This is sometimes described as functional incontinence.³

Factors may include:

• Arthritis or joint pain that makes movement slower
• Balance problems that make rushing unsafe
• Recovery from an injury or surgery
• Weakness or physical limitations caused by a long-term condition
• Difficulty transferring from a bed or chair
• Stairs, narrow doorways or bathrooms located far from the main living area
• Clothing that is difficult to remove quickly

5. Effects of Medical Treatment

Bowel leakage may begin during or after treatment for another health problem. Symptoms may appear immediately, during recovery or months or years later.

A few examples include:

• Pelvic radiation: Radiation for prostate, cervical, rectal or other pelvic cancers can affect the tissues and nerves involved in bowel control.
• Colorectal or pelvic surgery: Surgery involving the anus, rectum or nearby organs may cause temporary or lasting changes in bowel function.
• Chemotherapy: Some treatments can contribute to diarrhea or changes in stool consistency.
• Medication side effects: Certain medications may cause diarrhea, constipation or urgency.
• Gallbladder removal: Some people experience ongoing diarrhea or urgency after gallbladder surgery.¹

Pelvic radiation, rectal surgery and inflammatory bowel disease may also cause inflammation or scarring that reduces the rectum’s ability to stretch and hold stool.¹

If your symptoms began after a procedure, treatment or medication change, tell your care team, even if some time has passed.

6. Health Conditions Associated with Bowel Leakage

Several digestive, neurological and pelvic health conditions may contribute to accidental bowel leakage.

These include:

• Irritable bowel syndrome, particularly when diarrhea or urgency is frequent
• Crohn’s disease or ulcerative colitis
• Multiple sclerosis
• Parkinson’s disease
• Stroke or spinal cord injury
• Diabetes-related nerve damage
• Rectal prolapse
• Hemorrhoids
• Pelvic floor dysfunction^1,3

Hemorrhoids and rectal prolapse can sometimes prevent the muscles around the anus from closing completely, allowing small amounts of stool or mucus to escape.¹

Having one of these conditions does not mean bowel leakage is inevitable. However, it may provide an important clue that helps a healthcare provider identify why symptoms are occurring.

Possible Causes of Bowel Leakage at a Glance

When Should You See a Healthcare Provider for Bowel Leakage?

Consider making an appointment if you experience:

• Bowel leakage that is new or happening more often
• A change in your normal bowel habits
• Frequent diarrhea, constipation or urgent bowel movements
• Stool passing without you feeling it happen
• Skin irritation, itching or soreness caused by moisture
• Symptoms that affect work, travel, sleep, exercise or social activities
• Changes that affect your confidence or independence

You do not need to wait until accidents become frequent or severe. Earlier evaluation may make it easier to identify contributing factors and discuss available options.

Talk with a healthcare provider if bowel leakage is frequent or severe, affects your quality of life, or causes emotional or social distress.^1,3

What Treatments Are Available for Bowel Leakage?

leakage treatment is based on what is causing the problem, how often it happens and how it affects your everyday life. A healthcare provider may recommend one approach or a combination of treatments.

Options may include:

• Dietary changes: Adjusting fiber, fluid intake or foods that affect stool consistency
• Medication review: Determining whether a prescription or over-the-counter medication may be worsening diarrhea or constipation
• Bowel training: Establishing routines that encourage more predictable bowel movements
• Pelvic floor therapy: Physical therapy focused on strengthening the muscles involved in bowel control
• Biofeedback therapy: Improving muscle coordination and your ability to recognize and respond to rectal sensations
• Skin protection and backup products: Using pads, briefs or barrier products to protect clothing and skin
• Prescription devices: Helping prevent or manage leakage without surgery
• Nerve stimulation or other procedures: Addressing certain nerve, muscle or structural problems
• Surgery: Treating specific injuries or conditions when other approaches do not provide enough relief^2,5,6

Your treatment plan should reflect your symptoms, medical history, personal goals and how bowel leakage affects your daily routine.

Frequently Asked Questions About Bowel Leakage

What causes bowel leakage in adults?

Common causes of bowel leakage in adults include chronic diarrhea, constipation with overflow, weakened pelvic floor or anal muscles, nerve damage, mobility limitations, medical treatments and digestive or neurological conditions. More than one factor may be involved.^1,3

Why am I leaking stool without knowing it?

Stool may leak without your awareness when the nerves that sense fullness in the rectum are damaged or not working properly. This is sometimes called passive fecal incontinence. Diabetes-related nerve damage, neurological conditions, spinal injuries, repeated straining and certain surgeries may affect sensation or bowel control.^1,3

Is bowel leakage the same as fecal incontinence?

Bowel leakage, accidental bowel leakage, bowel incontinence and fecal incontinence generally describe the accidental passage of stool. Symptoms can range from occasional staining to frequent accidents or stool passing without awareness.^1,3

Can constipation cause bowel leakage?

Yes. Hard stool can collect in the rectum and allow softer or watery stool to leak around it. This is known as overflow leakage. Constipation may also stretch and weaken the rectal muscles over time.^1,3

Can diarrhea cause bowel leakage?

Yes. Loose or watery stool fills the rectum quickly and is more difficult to hold than formed stool. Diarrhea may also create sudden urgency, leaving less time to reach a bathroom.^1,3

Is bowel leakage a normal part of aging?

No. The likelihood of bowel leakage may increase with age, but it should not simply be dismissed as a normal or unavoidable part of getting older. Muscle weakness, nerve changes, constipation, medications and mobility limitations can be evaluated and managed.²

Can bowel leakage be treated?

Many people have options for reducing or managing bowel leakage. Depending on the cause, a healthcare provider may recommend dietary changes, medication, bowel training, pelvic floor therapy, biofeedback, prescription devices, nerve stimulation or surgery.^2,6

When should I talk to a doctor about bowel leakage?

Talk with a healthcare provider when leakage is new, becoming more frequent, causing skin problems or affecting your daily activities, confidence or independence. Seek immediate medical care for blood in your stool, black or tarry stool, severe abdominal pain, fainting or significant weakness.^1,3,5

Could StaySure^® help manage bowel leakage?

StaySure^® is a prescription-only silicone insert designed to help prevent accidental bowel leakage. It may be considered when a person needs additional protection beyond lifestyle or behavioral approaches. StaySure^® does not treat the underlying cause of leakage, and a healthcare provider must determine whether it is appropriate for you. Learn more about StaySure^®.

References

1. National Institute of Diabetes and Digestive and Kidney Diseases. (2017, July). Symptoms and causes of fecal incontinence. U.S. Department of Health and Human Services, National Institutes of Health. https://www.niddk.nih.gov/health-information/digestive-diseases/bowel-control-problems-fecal-incontinence/symptoms-causes
2. National Institute of Diabetes and Digestive and Kidney Diseases. (2017, July). Treatment of fecal incontinence. U.S. Department of Health and Human Services, National Institutes of Health. https://www.niddk.nih.gov/health-information/digestive-diseases/bowel-control-problems-fecal-incontinence/treatment
3. Mayo Clinic. (2024, November 27). Fecal incontinence – Symptoms and causes. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/fecal-incontinence/symptoms-causes/syc-20351397
4. Johns Hopkins Medicine. (2026, June 24). FODMAP diet – what you need to know. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/expert-qa/fodmap-diet-what-you-need-to-know
5. Mayo Clinic. (2026, May 14). Gastrointestinal bleeding – symptoms and causes. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/gastrointestinal-bleeding/symptoms-causes/syc-20372729
6. Mayo Clinic. (2024, November 27). Fecal Incontinence – diagnosis and treatment. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/fecal-incontinence/diagnosis-treatment/drc-20351403