Stool eating is one of the most common and most disgusting habits dogs develop, and it’s far more normal than you’d think. The behavior, called coprophagia, has deep evolutionary roots and is usually not a sign that something is seriously wrong with your dog. But in some cases it points to a medical or behavioral issue worth addressing, and it carries real health risks, especially when cat feces are involved.
It’s an Instinct From Wolves
The leading scientific explanation traces stool eating back to your dog’s wolf ancestors. Wolves living in dens had a hygiene problem: if a sick or injured pack member defecated in the resting area, the feces would become dangerous within about two days as parasite eggs developed into infective larvae. Eating fresh feces before those larvae matured was a way to keep the den safe. The parasites hadn’t yet reached a stage where they could cause infection, so consuming them quickly was actually protective.
This “den sanitation” instinct appears to have carried forward into domestic dogs. Mother dogs routinely eat their puppies’ feces for the first few weeks of life, keeping the whelping area clean. Many dogs seem to extend that same impulse to any fresh stool they encounter, whether it belongs to another dog, a cat, or wildlife. It’s not that your dog is confused or broken. The wiring is just still there.
Why Cat Poop Is Especially Tempting
If your dog makes a beeline for the litter box, there’s a straightforward reason: cat food is significantly richer than dog food, and cats don’t absorb every bit of it. Dry cat food averages about 34% protein and 18% fat, compared to roughly 22% protein and 14% fat in dry dog food. Cats are obligate carnivores, so their diets are packed with animal-based nutrients. What passes through a cat’s digestive system still contains enough protein and fat residue to smell like a snack to your dog. To a dog’s nose, the litter box is essentially a buffet of concentrated, high-protein treats.
Medical Causes Worth Ruling Out
Sometimes stool eating signals that your dog isn’t properly absorbing nutrients from their own food. The most common medical culprit is a condition called exocrine pancreatic insufficiency (EPI), where the pancreas doesn’t produce enough digestive enzymes. Without those enzymes, your dog can’t break down fats, starches, and proteins into forms the body can absorb. The food passes through largely undigested, producing greasy, foul-smelling stools. Your dog may lose weight despite eating normal amounts, and the undigested nutrients in their stool (or another animal’s) become appealing because the dog is genuinely hungry at a cellular level.
EPI also causes bacterial overgrowth in the intestines, since the unabsorbed nutrients feed gut bacteria instead of the dog. This compounds the malnutrition. If your dog is eating feces and also losing weight, producing unusually greasy or voluminous stools, or seems constantly hungry, a vet visit is worthwhile. Blood work and stool tests can identify enzyme deficiencies and rule out other absorption problems.
Behavioral and Environmental Triggers
Not every poop-eating dog has a medical issue. Several behavioral patterns drive the habit:
- Anxiety and stress. Dogs experiencing separation anxiety or adjusting to a big change, like a new pet in the household or a move to a new home, sometimes develop coprophagia as a stress response.
- Boredom. Dogs that don’t get enough mental stimulation or playtime may turn to stool eating simply because there’s nothing better to do. This is especially common in young puppies who spend long stretches confined or crated during their first few months.
- Fear of punishment. Dogs who’ve been scolded for indoor accidents sometimes eat the evidence to avoid getting in trouble. This also happens with older dogs who have arthritis or cognitive decline and can’t always make it outside in time. They don’t want to upset you, so the feces disappear.
The punishment connection is worth paying attention to. If you’ve reacted strongly to house-soiling accidents in the past, your dog may have learned that the presence of poop leads to a bad outcome, and eating it is the simplest solution they can come up with.
Health Risks of Eating Feces
The biggest concern is parasites. Dog and cat feces can carry roundworms, hookworms, whipworms, giardia, and coccidia. Cat feces specifically may contain Toxoplasma gondii, the parasite responsible for toxoplasmosis. While toxoplasmosis is more of a concern for humans (especially pregnant women) than for most adult dogs, the roundworm risk is real for both your dog and your family. The CDC identifies Toxocara canis, a common dog roundworm, as the most frequent cause of toxocariasis in people, and the parasite cycle is perpetuated when dogs ingest contaminated feces.
Feces can also contain bacteria like salmonella and campylobacter, and if your dog has been eating cat stool from a litter box, they may also ingest clumping litter, which can cause intestinal blockages in smaller dogs. Keeping your dog’s parasite prevention current is important if they have access to any animal’s feces.
How to Stop the Behavior
Management is the fastest fix. If the litter box is the problem, move it somewhere your dog can’t reach. Baby gates, covered litter boxes with small entry holes, or placing the box on a raised surface all work. For outdoor dog poop, pick it up immediately. The less opportunity your dog has to practice the behavior, the faster it fades.
Training a solid “leave it” command gives you a reliable way to interrupt the behavior in real time. Start by placing a treat in your closed fist and letting your dog sniff, paw, and nose at it. The moment they pull back or lose interest, mark that moment with a word like “yes” and reward them with a different treat. You’re teaching them that ignoring something appealing is exactly what earns them a reward. Once they’re consistent with your fist, practice with treats on the floor (covered by your hand at first, then uncovered), gradually building up to real-world distractions.
The goal is for your dog to develop an automatic habit of looking to you before picking up anything off the ground, rather than needing to hear a command every time. This takes weeks of consistent practice, and the key rule is to never use the cue in a situation where you know your dog won’t respond. If they blow past your “leave it” and grab the feces anyway, you’ve just trained them that the command is optional. Go back a step and practice with easier distractions first.
Addressing the Root Cause
If your dog started eating feces suddenly, or does it obsessively, look for what changed. A new schedule, less exercise, a new pet, or a dietary switch can all trigger the behavior. Increasing daily exercise and adding puzzle feeders or food-dispensing toys often helps with boredom-related coprophagia, especially in young, high-energy dogs.
For dogs where a medical cause has been identified, treating the underlying condition usually resolves the stool eating. Dogs with EPI, for example, are given enzyme supplements with every meal, and once they’re properly absorbing nutrients again, the drive to seek out feces typically drops. If no medical cause is found and the behavior persists despite management and training, a veterinary behaviorist can help identify whether anxiety or a compulsive pattern is at play and build a more targeted plan.