Fecal Incontinence in Dogs: Causes, Diagnosis, and Care

The distinction matters for diagnosis and treatment:

• Fecal incontinence: Stool passes involuntarily. The dog does not posture, may not be aware, and the stool can be formed or soft.
• Diarrhea: Frequent, loose, or liquid stools driven by gastrointestinal urgency. The dog typically shows awareness and attempts to reach an appropriate area.
• Indoor accidents (behavioral): The dog has normal bowel control but eliminates indoors due to cognitive decline, anxiety, insufficient outdoor access, or incomplete housetraining. Posturing and awareness are usually present.

Chronic diarrhea can overwhelm even a healthy sphincter and mimic incontinence. Similarly, cognitive dysfunction syndrome in senior dogs can cause house-soiling that looks like incontinence but stems from disrupted learned behavior rather than physical inability. A veterinary workup distinguishes these conditions.

Causes of Dog Bowel Incontinence

Dog bowel incontinence can result from a wide range of underlying problems:

Neurologic causes. Spinal cord injuries, intervertebral disc disease (IVDD), degenerative myelopathy, lumbosacral stenosis, spinal tumors, or sacrocaudal nerve damage can disrupt the neural pathways controlling the anal sphincter and rectal sensation. When these nerves are damaged, the dog may have no awareness that stool is passing.

Anal sphincter dysfunction. The anal sphincter can weaken with age, chronic perianal inflammation, or after surgical procedures in the perianal or rectal area. A weakened sphincter cannot maintain closure, and stool leaks—especially when the dog is relaxed or asleep.

Colorectal disease. Chronic colitis, inflammatory bowel disease (IBD), colorectal polyps or tumors, or rectal strictures can impair the rectum's ability to store stool normally, leading to overflow incontinence or urgency.

Cognitive dysfunction. Senior dogs with cognitive dysfunction syndrome (CDS) may lose awareness of elimination habits—not from physical inability but from neurologic decline affecting learned behavior and spatial orientation.

Medication effects. Certain medications, including some sedatives and gastrointestinal motility drugs, can affect sphincter tone or bowel motility.

Chronic diarrhea. Persistent diarrhea from any cause increases urgency and volume, overwhelming even normal sphincter function.

Reservoir vs Sphincter Incontinence

Two mechanistically distinct types of fecal incontinence are recognized, and distinguishing them guides both diagnosis and treatment.

Reservoir incontinence occurs when the rectum cannot store stool adequately. Causes include inflammatory bowel disease, rectal tumors, surgical changes to rectal capacity, or chronic diarrhea that overwhelms storage. Dogs with reservoir incontinence often show urgency—they attempt to reach an appropriate spot but cannot wait long enough.

Sphincter incontinence occurs when the anal sphincter is too weak to hold stool in the rectum. The dog typically has no awareness of leakage. This type is more commonly associated with nerve damage, age-related muscle weakening, or prior perianal surgery.

Observable differences:

• Reservoir type: Frequent, urgent defecation attempts; stool may be soft or formed; the dog appears aware of the problem.
• Sphincter type: Stool leaks passively without awareness, often during rest or sleep; stool is usually formed.

A combination of the two is possible, particularly in senior dogs with multiple concurrent conditions.

How Veterinarians Diagnose Fecal Incontinence

Because treatment depends entirely on the underlying cause, a thorough diagnostic workup is essential—especially in older dogs where several contributing factors may coexist.

• History and stool diary. When accidents occur, stool consistency, awareness versus passive leakage, and any associated signs (hind-limb weakness, urinary changes) help the veterinarian categorize the problem.
• Neurologic examination. Testing spinal reflexes, tail tone, perineal sensation, and gait identifies neurologic involvement.
• Rectal examination. Digital palpation assesses sphincter tone, rectal masses, strictures, or perianal abnormalities.
• Laboratory testing. Blood work, fecal analysis, and thyroid screening rule out systemic disease, parasites, infection, or metabolic causes.
• Imaging. Radiographs or MRI of the spine are indicated when neurologic disease is suspected. Abdominal ultrasound can identify colonic or rectal masses.
• Colonoscopy or proctoscopy. Direct visualization is considered when inflammatory or neoplastic colorectal disease is suspected.

Treatment and Daily Management

Treatment targets the underlying cause whenever one can be identified:

• Neurologic causes. Surgical decompression for disc disease or lumbosacral stenosis, if indicated. When nerve damage is permanent, management focuses on hygiene and quality of life.
• Colorectal disease. Anti-inflammatory therapy for IBD, surgical removal of polyps or masses, or dietary management for chronic colitis.
• Sphincter weakness. Medications that increase sphincter tone may be tried under veterinary guidance. Pelvic floor or hind-limb strengthening exercises can help some dogs.
• Cognitive dysfunction. Environmental management, cognitive enrichment, and medications targeting CDS may reduce house-soiling episodes.
• Dietary adjustment. A highly digestible diet with appropriate fiber can improve stool consistency and reduce urgency. Changes should be guided by the veterinarian based on the underlying diagnosis.
• Scheduled outdoor access. Offering more frequent elimination opportunities—especially after meals, upon waking, and before bedtime—reduces the chance of indoor accidents.
• Skin and hygiene care. Keep the perianal area clean and dry. Barrier creams or ointments can protect skin from irritation and infection caused by chronic moisture.
• Doggy diapers or belly bands. Practical for managing passive leakage. Check and change frequently to prevent skin breakdown.

Nighttime leakage is one of the most common and distressing presentations of fecal incontinence in older dogs. A structured routine can help:

• Offer a final outdoor trip as close to bedtime as possible.
• Use waterproof mattress pads under washable bedding for easy cleanup.
• Position the bed on an easy-to-clean surface away from carpeting.
• Consider a late-evening feeding schedule adjustment (with veterinary guidance) so the bowel empties before sleep.
• Check and clean the dog promptly in the morning to prevent skin irritation.

Nighttime accidents are not a choice. Punishing or scolding a dog for involuntary leakage increases stress and can worsen the problem. A broader guide to managing incontinence covers additional practical strategies.

When Bowel Incontinence Is Urgent

Most cases of fecal incontinence develop gradually and can be evaluated at a scheduled veterinary appointment. However, seek prompt or emergency care if:

• Sudden onset with hind-limb weakness, difficulty walking, or loss of bladder control. These signs suggest an acute spinal or neurologic emergency such as IVDD or fibrocartilaginous embolism.
• Blood in the stool or significant rectal bleeding.
• Severe pain, straining, or abdominal distension.
• Rapid weight loss or decline in overall condition.
• Simultaneous loss of urinary and fecal control in a previously continent dog.

Early intervention for neurologic emergencies can significantly affect the outcome. Do not wait for a scheduled appointment if these signs are present.

This article is for educational purposes only and does not replace professional veterinary diagnosis and treatment. If your pet develops bowel control problems, consult a veterinarian.

Sources:

1. Predictors of urinary or fecal incontinence in dogs with thoracolumbar injury
2. Bowel Incontinence in Dogs
3. Managing Fecal Incontinence in Pets: Tips From Hospice Veterinarian, Dr. Mary Gardner

Related articles: Caring for an Incontinent Pet · Inappropriate Elimination in Senior Dogs · Urinary Incontinence in Dogs · Constipation Causes in Dogs