How to Stop Dogs Eating Faeces: The Science Behind Coprophagia

Why Dogs Eat Faeces: A Direct Answer

Coprophagia is one of the most common behavioral complaints among dog owners, yet it remains widely misunderstood. A 2012 study presented at the American Veterinary Society of Animal Behavior annual meeting by Dr. Benjamin Hart at UC Davis found that approximately 16% of dogs engage in frequent coprophagia (defined as being observed eating faeces at least six times). The behavior is significantly more common in multi-dog households, greedy eaters, and certain breeds including Labrador Retrievers and Shetland Sheepdogs.

Understanding the science behind this behavior is the first step toward effectively managing it. Rather than viewing coprophagia as a "bad habit," modern canine science recognizes it as a complex interplay of evolutionary instinct, neurobiology, and environmental factors.

The Evolutionary Basis of Coprophagia

To understand why your dog eats faeces, we need to look at their evolutionary ancestors. Wild canids — wolves, coyotes, and foxes — exhibit coprophagic behavior under specific circumstances that reveal its adaptive value:

• Den hygiene and predator avoidance: Mother wolves consume the faeces of their pups during the first weeks of life to keep the den clean and eliminate scent trails that could attract predators. This maternal behavior is hardwired into the canine brain and persists in domestic dogs regardless of whether they have offspring.
• Nutrient recycling during scarcity: When prey is limited, wild canids may re-consume faeces to extract remaining nutrients, particularly B vitamins produced by gut bacteria during the first digestive pass. Herbivore faeces (rabbit, deer) contains partially digested plant matter rich in volatile fatty acids that canids can utilize.
• Social learning within packs: Juvenile wolves learn foraging behaviors by observing adults. Pups that observe coprophagia may adopt the behavior, which persists into adulthood even when nutritional need is absent.
• Territory investigation: Canids investigate faecal deposits from other animals to gather chemical information about territory boundaries, reproductive status, and health of neighboring individuals.

The domestication of dogs over the past 15,000–40,000 years has not eliminated these ancestral neural circuits. According to the Merck Veterinary Manual, coprophagia in domestic dogs represents a normal behavior expressed in an abnormal context — your living room rather than the wild.

The Physiological Mechanisms Behind the Behavior

Several physiological systems interact to produce coprophagic behavior:

The Vomeronasal Organ and Chemical Detection

Dogs possess a highly developed vomeronasal organ (VNO) located in the roof of the mouth, connected to the accessory olfactory bulb. This organ detects pheromones and volatile organic compounds in faecal matter. When a dog investigates faeces, the VNO sends signals to the amygdala and hypothalamus, triggering interest and potential consumption. This is the same mechanism dogs use when they "flehmen" — the open-mouthed sniffing behavior you may observe.

Digestive Enzyme Deficiencies and Malabsorption

Dogs with exocrine pancreatic insufficiency (EPI) produce insufficient digestive enzymes (lipase, amylase, protease). Their faeces contains undigested fats, proteins, and carbohydrates that retain caloric value and palatability. These dogs are genuinely driven to re-consume their faeces because it represents a lost meal. EPI affects approximately 1 in 50 German Shepherds and is also seen in Collies and English Setters.

Intestinal parasites — particularly roundworms (Toxocara canis), hookworms (Ancylostoma caninum), and giardia — compete for nutrients in the gut, creating a state of functional malnutrition even when dietary intake appears adequate. The dog's hypothalamic hunger center responds by increasing food-seeking behavior, which may include coprophagia.

Dopamine Reward Pathways

Once a dog consumes faeces and finds it palatable (particularly cat faeces, which is high in protein and fat), the mesolimbic dopamine pathway reinforces the behavior. Each successful consumption strengthens the neural association between "faeces" and "reward," making the behavior more likely to recur. This is identical to the mechanism that reinforces any learned food-seeking behavior and explains why coprophagia becomes habitual rather than occasional.

Gut Microbiome Influence

Emerging research in canine gastroenterology suggests that the gut-brain axis — communication between intestinal microbiota and the central nervous system via the vagus nerve — may influence food preferences and consumption behaviors. Dogs with dysbiosis (imbalanced gut bacteria) may exhibit altered appetite regulation and pica (consumption of non-food items), though direct evidence linking microbiome composition to coprophagia specifically remains limited as of 2026.

How to Stop Dogs Eating Faeces: Evidence-Based Strategies

Based on veterinary behavioral science, here is a structured protocol for addressing coprophagia:

Step 1: Veterinary Health Screening

Before attempting behavioral modification, rule out medical causes. Request the following from your veterinarian:

Step 2: Dietary Optimization

Many cases of coprophagia resolve with dietary adjustments that address nutritional gaps or improve digestibility:

• Switch to a highly digestible diet: Look for AAFCO statements confirming "complete and balanced" nutrition. Diets with a dry matter digestibility above 85% leave fewer palatable residues in faeces. Brands like Hill's Science Diet, Royal Canin, and Purina Pro Plan offer high-digestibility formulations.
• Increase feeding frequency: Splitting daily rations into 3 meals instead of 1–2 reduces hunger-driven coprophagia by maintaining more stable blood glucose levels throughout the day.
• Consider a veterinary-formulated enzyme supplement: Products containing pancrelipase (such as Pancrezyme or generic pancreatic enzyme replacements) can improve nutrient absorption in dogs with subclinical pancreatic insufficiency. These require veterinary prescription and typically cost $60–$120 per month.
• Add dietary deterrents with caution: Commercial products like For-Bid (made from wheat gluten and vegetable derivatives) or NaturVet Deterrence Powder (containing Yucca schidigera and garlic derivatives) are designed to make faeces taste unpleasant. The UC Davis study by Dr. Hart found that owner-reported success rates for these products ranged from only 2% to 15%, making them unreliable as sole interventions. They may work as part of a multi-modal approach.

Step 3: Environmental Management

This is the single most effective intervention and requires zero training:

• Immediate faecal removal: Pick up all faeces within 2 minutes of elimination. Dogs rarely consume their own faeces immediately after defecation — the behavior typically occurs when faeces is left unattended for 10+ minutes. Use biodegradable waste bags and maintain a consistent yard-cleaning schedule (minimum twice daily for multi-dog households).
• Leash supervision during elimination: Keep your dog on a 6-foot leash during bathroom breaks. After elimination, immediately call your dog to you using a trained recall cue and reward with a high-value treat (freeze-dried liver, chicken, or cheese — approximately 5–10 calories per reward).
• Cover or restrict access to cat litter boxes: Cat faeces is a potent coprophagia trigger due to its high protein and fat content. Use top-entry litter boxes, install baby gates with cat-sized openings, or place litter boxes behind microchip-activated cat doors (such as the SureFlap Microchip Pet Door, approximately $90–$130).
• Muzzle training for severe cases: A basket muzzle (such as the Baskerville Ultra or Jafco Clear Vinyl muzzle, $15–$30) allows normal panting and drinking while preventing faecal consumption during outdoor walks. Pair muzzle introduction with positive reinforcement — feed treats through the basket openings for 5–10 minute sessions over 1–2 weeks before using in the field.

Step 4: Behavioral Training Using Positive Reinforcement

Force-free training methods are both more effective and more humane than punishment-based approaches:

• "Leave it" training protocol: Begin with low-value items (a dry biscuit on the floor) and progressively work up to higher-value temptations. When your dog looks away from the item on cue, mark the behavior with a clicker or verbal "yes" and reward with a treat from your hand. This typically takes 2–4 weeks of daily 5-minute sessions to generalize to outdoor environments.
• Differential reinforcement of incompatible behavior (DRI): Train your dog to perform a behavior that physically prevents coprophagia after elimination — such as "come and sit" or "touch" (nose-targeting your hand). Reward heavily (3–5 consecutive treats) for compliance. This replaces the coprophagia habit loop with a new, rewarded behavior.
• Counter-conditioning for habitual coprophages: If your dog has a strong history of eating faeces, pair the sight/smell of faeces with an incompatible positive experience — such as a scatter feed of high-value treats thrown in the opposite direction. Over 3–6 weeks, the dog learns that faeces predicts treats coming from elsewhere, reducing direct interest in the faeces itself.

Common Misconceptions About Coprophagia

Breed Variations and Risk Factors

Coprophagia is not equally distributed across dog breeds. The UC Davis survey data and subsequent veterinary behavioral observations have identified several patterns:

• High-prevalence breeds: Labrador Retrievers, Golden Retrievers, Shetland Sheepdogs, and terrier breeds (particularly Jack Russell Terriers) show above-average coprophagia rates. These breeds tend to share traits of high food motivation, oral fixation, and greedy eating styles.
• Low-prevalence breeds: Small toy breeds (Pomeranians, Chihuahuas) and brachycephalic breeds (Pugs, Bulldogs) show lower rates, possibly due to less pronounced scavenging drive or physical difficulty in consuming faeces.
• Age factor: Puppies under 12 months show the highest rates of coprophagia, with a natural decline as they mature. However, dogs that continue the behavior past 12 months are likely to persist without intervention.
• Household composition: Dogs in multi-dog households are 2–3 times more likely to engage in coprophagia, likely due to social learning and competition-driven resource guarding of faecal material.
• Spay/neuter status: No significant correlation has been established between reproductive status and coprophagia prevalence.

When Coprophagia Signals a Medical Problem

Several medical conditions present with coprophagia as a secondary symptom:

• Exocrine pancreatic insufficiency (EPI): The pancreas fails to produce adequate digestive enzymes. Dogs produce large volumes of pale, greasy, foul-smelling faeces and often eat it compulsively. Treatment involves lifelong pancreatic enzyme supplementation (Pancrezyme or equivalent, $60–$150/month) and typically resolves coprophagia within 2–4 weeks.
• Intestinal parasitism: Heavy roundworm or hookworm burdens cause nutrient malabsorption. A faecal flotation test ($45–$85) can diagnose this, and deworming with fenbendazole (Panacur, approximately $15–$30 per course) or a broad-spectrum product like Drontal Plus ($12–$25 per dose) resolves the underlying cause.
• Diabetes mellitus: Uncontrolled diabetes causes polyphagia (excessive hunger) and may drive coprophagia as a hunger response. Blood glucose monitoring and insulin therapy address the root cause.
• Cushing's disease (hyperadrenocorticism): Excess cortisol production causes ravenous appetite. Diagnosis requires an ACTH stimulation test or low-dose dexamethasone suppression test ($150–$300). Treatment with trilostane (Vetoryl, $50–$120/month) manages the condition.
• Cognitive dysfunction syndrome (CDS): Senior dogs (typically 10+ years) with canine cognitive decline may exhibit coprophagia as a compulsive or disoriented behavior. Management includes environmental enrichment, selegiline (Anipryl, prescription required), and SAMe supplementation.

Frequently Asked Questions