Why do dogs eat cat poop? The real reasons and how to stop it

Dogs eat cat poop primarily because cat feces smells and tastes like concentrated, undigested protein and fat. Cat food runs higher in protein and fat than dog food, and a lot of that comes through in the litter box largely undigested, which makes it read to a dog’s nose as a snack rather than waste. Layer scavenging instinct on top of that, and a litter box becomes one of the most reliably interesting things in the house.

This isn’t rare or particularly abnormal. In a UC Davis survey of over 1,500 dogs led by researcher Benjamin Hart, 16 to 23% of dogs ate stool frequently (six or more times observed), and 23 to 49% did it at least once. About 10% of shelter dogs were reported eating feces within four weeks of adoption. If your dog raids the litter box, you’re not dealing with a broken dog, just a very common and very fixable habit.

Why does my dog eat cat poop specifically

Cat poop is more appealing to dogs than most other stool because of that protein-and-fat content and because cats, as obligate carnivores, produce waste with a stronger, meatier odor profile. Dogs are scavengers by nature, and a litter box is basically an accessible, unguarded snack station. There’s no deeper psychological issue required to explain this. It’s a straightforward matter of smell, taste, and easy access, per PetMD and AKC’s reporting on the behavior.

Why do dogs eat poop in general

The leading theory, based on Hart’s research published in Veterinary Medicine and Science, is that coprophagy is a leftover instinct from ancestral wolves keeping den areas clean of parasite-infected stool. The evidence backing this: dogs overwhelmingly go for fresh stool, with 85% of documented cases involving feces less than two days old. Stool that age hasn’t yet become infective with parasite eggs, which supports the idea that this evolved as a den-hygiene behavior rather than a hunt for nutrients. Notably, Hart’s data found no differences in age, sex, neuter status, diet type, or house-training ease between dogs that do this and dogs that don’t. Some breeds (terriers, Beagles, Shetland Sheepdogs, and Labradors) show up more often as opportunistic scavengers, while poodles are underrepresented.

Is it a nutritional deficiency

Usually not. Commercial dog foods sold today are formulated to be nutritionally complete, so a dog eating a standard commercial diet is very unlikely to be missing nutrients in a way that would drive this. Veterinary Partner notes that most cases of coprophagia genuinely linked to diet trace back to home-cooked meals put together without a veterinary nutritionist’s input, not to a bag of complete-and-balanced kibble. If your dog is on a standard commercial diet and eating poop, look at behavior and environment before you start second-guessing the food.

When it’s a medical issue, not a habit

Sudden-onset coprophagia in an adult dog that never did this before is worth a vet visit. A few conditions specifically cause it:

Exocrine pancreatic insufficiency (EPI): 17% of dogs diagnosed with EPI showed coprophagia, because their stool contains undigested fat and protein their body never absorbed, which makes it genuinely appetizing.
Intestinal parasites, malabsorption disorders, thyroid disease, diabetes, and Cushing’s disease can all increase appetite or interfere with digestion in ways that trigger the behavior.
Medications that boost appetite, including steroids, benzodiazepines, and gabapentin, are a less obvious but documented cause.

A puppy dabbling in this is developmentally normal and often self-resolves. An older dog who starts suddenly deserves a checkup.

Why do dogs eat grass

Grass-eating is a separate behavior from coprophagy, and it’s just as common: most vets consider occasional grass-eating normal dog behavior, not a sign of illness. Some dogs do it to induce vomiting when their stomach is upset, some seem to just like the taste or texture, and for many it looks like simple foraging boredom-relief, similar to why a bored dog gets into the trash. It’s only a concern if it’s frequent, obsessive, or paired with vomiting, lethargy, or appetite loss, in which case a vet visit rules out gastrointestinal issues.

Why do dogs lick you

Licking is typically affection, attention-seeking, or a learned habit that gets reinforced because humans react to it (with a laugh, a pet, or even a mild scolding, which a dog may still read as attention). It can also be exploratory, since a dog’s mouth is a primary way of gathering information about the world, and mildly salty human skin is its own draw. This is a different behavioral category from coprophagy: one is investigative and social, the other is scavenging-driven.

Health risks of a dog eating cat poop

This is where it stops being just an unpleasant habit and becomes a real health question. Cat feces can carry roundworms (Toxocara cati), hookworms (Ancylostoma tubaeforme), giardia, coccidia, tapeworms, and bacteria like E. coli, Salmonella, and Campylobacter, according to veterinary sources including Rover and PetMD. Cats infected with these parasites often show no symptoms at all, so a perfectly healthy-looking cat can still be shedding infective organisms in its litter box.

Toxoplasma gondii is a particular concern. Per Dutch.com, it’s commonly present in cat feces and can cause toxoplasmosis in dogs, with puppies and immunocompromised dogs most at risk. There’s also a mechanical risk from clumping litter: bentonite and other clumping agents can cause intestinal blockages if ingested, especially in smaller dogs, since the material is designed to swell and clump on contact with moisture.

If your dog eats cat feces and later shows lethargy, vomiting, diarrhea, or weight loss, get a fecal test done. Since cats can be asymptomatic carriers, you can’t rule out parasites just because the cat seems fine.

What actually stops it (and what doesn’t)

The honest answer, backed by Hart’s research, is that management beats training here. Commercial anti-coprophagia products, food additives, and taste deterrents have a dismal track record, with success rates in the 1 to 4% range in studies. Punishment tends to backfire too, since it can just teach the dog to eat the evidence faster while you’re not looking, and it can worsen anxiety-driven versions of the behavior. One small trial found citronella spray cut the behavior by roughly 66% in Labrador Retrievers, but long-term results weren’t tracked, so treat that as a maybe, not a fix.

What consistently works is removing access:

Scoop the litter box immediately and often. If there’s nothing fresh to find, there’s nothing to eat.
Use a top-entry or elevated litter box rather than relying on a covered box alone. Top-entry designs make it physically harder for a dog to reach in, while a simple hood doesn’t stop a determined dog and can even trap odor a cat dislikes.
Add a physical barrier: a baby gate with a cat-sized cutout, a cracked door too narrow for the dog, or a separate laundry-room setup the dog can’t access at all.
Consider a self-cleaning litter box. Removing waste automatically after each use cuts down on the scent cues that draw a dog in, on top of being a convenience upgrade for you.

Basic obedience cues like “leave it,” plus rewarding the dog for ignoring the box, can help around the edges, but per PetMD and Hart’s own conclusions, training rarely eliminates the behavior on its own if the dog still has physical access. Environmental management is the part that actually holds up.

The bottom line

A dog eating cat poop is common, driven by scent and scavenging instinct rather than a nutrient gap, and only occasionally a sign of an underlying medical issue. It’s also a real infection risk, so the fix isn’t a spray or a stern voice, it’s keeping the litter box out of reach: scoop constantly, go top-entry or gated, and get your dog checked if the habit shows up suddenly in adulthood or comes with other symptoms.

Frequently asked questions

Why is my dog eating poop from their own species, not just cats?

Dogs sometimes eat their own or other dogs’ stool for the same scavenging and scent-driven reasons they go after cat feces, and researcher Benjamin Hart’s data suggests it’s tied to an evolved instinct to remove fresh, potentially parasite-carrying stool from den areas. It’s most often directed at stool under two days old. Multi-dog households tend to see it more, partly because it can become a learned behavior copied from another dog.

Can eating cat poop make my dog sick right away?

It can, though many dogs show no immediate symptoms. Watch for vomiting, diarrhea, lethargy, or appetite loss in the days after, since these can signal a parasitic or bacterial infection picked up from the litter box. If any of these appear, a vet visit with a fecal test is the right next step, since infected cats often show no signs themselves.

Do covered litter boxes stop dogs from getting into the litter box?

Not reliably on their own. A covered box alone has a low success rate because determined dogs can still push through or flip open a hood, and covered boxes are less effective than top-entry or elevated designs. Pairing a top-entry box with a physical barrier like a baby gate works far better than design changes alone.

Should I switch litter types to protect my dog?

It can help reduce risk, since clumping bentonite litter poses a blockage hazard if ingested, particularly for smaller dogs. Switching to a non-clumping or dog-safer litter reduces one risk but doesn’t address the parasite and bacteria exposure, so it should be paired with access-control measures, not used as a standalone fix.