Why Does My Dog Eat Grass and Poop? (Pica and Coprophagia Explained)

You feed them premium kibble. You buy them organic treats. And yet, you watch in horror as your dog happily grazes on grass like a cow, or worse, snacks on… well, poop.

Why do they do it? Is something wrong with them? Are they sick?

These behaviors—eating non-food items (Pica) and eating feces (Coprophagia)—are two of the most common questions veterinarians get asked. They are gross to us, but in the dog world, they often have logical explanations.

Mystery 1: Why Do Dogs Eat Grass?

A commonly held belief is that dogs eat grass to make themselves vomit when they feel sick. The Truth: Studies show that fewer than 25% of dogs vomit after eating grass, and only 10% show signs of illness beforehand.

Reasons for Grazing:

1. They like the taste: Fresh spring grass is sweet and crunchy. It’s a salad bar.
2. Fiber Deficiency: Some dogs crave roughage.
3. Boredom: “I’m in the yard, nothing is happening, I guess I’ll mow the lawn.”
4. Ancestral Instinct: Wolves eat the stomach contents of prey (which includes fermented grass/berries).

Should you stop it? Generally, no. Unless the grass has been treated with pesticides or fertilizers (which are toxic), grazing is harmless.

Mystery 2: Why Do Dogs Eat Poop? (Coprophagia)

This one is harder to stomach. Why would a lovable animal do something so repulsive?

1. The “Mother” Instinct

Mother dogs eat their puppies’ poop to keep the den clean and hide the scent from predators. It is a hard-wired survival instinct. Some dogs retain this “cleaning” habit into adulthood.

2. Nutritional Deficiency (Malabsorption)

If a dog isn’t digesting their food properly, their poop might still contain undigested nutrients. To a dog, it smells like food because it is (partially) food.

• Check: Ask your vet to check for parasites or enzyme deficiencies (EPI).

3. “Delicious” Cat Poop

To a dog, the litter box is a vending machine of “Almond Rocas.” Cat food is high in protein, so cat poop is high in protein. It is a delicacy. The Fix: Put the litter box where the dog can’t reach it.

4. Attention Seeking

You run over yelling “NOOO!” every time they do it. Congratulations, you just made it a game.

How to Stop It

1. The “Leave It” Command: Train a rock-solid “Leave It.”
2. Immediate Pickup: Clean up the yard immediately. If there is no poop, they can’t eat it.
3. Dietary Additives: Products like “For-Bid” or feeding pineapple/pumpkin can make the poop taste bad (worse?) to the dog.
4. Vet Check: Rule out parasites.

When to Worry

• Pica (Non-Food Items): If your dog eats socks, rocks, or drywall, this is serious. It can cause a life-threatening blockage. This is often an OCD-like behavioral disorder or a sign of severe GI distress. See a vet immediately.

Summary

Grass eating is usually a quirk. Poop eating is usually a bad habit (or a cleaning instinct). While disgusting to us, it’s rarely an emergency. Keep the yard clean, keep the worming up to date, and maybe don’t let them kiss you immediately after a garden stroll.