Why Do Dogs Eat Grass? 7 Common Reasons

Many dogs like to eat grass from time to time. Here’s when it’s cause for concern.

We’ve all seen how livestock, including cows, sheep, and goats, love gnawing on grass. It’s fine for grazing to be their pastime because their stomachs are able to digest all of the cellulose in grass. Unlike those animals, dogs are omnivores, related to meat-eating hunters like wolves. Yet if you own a dog, you may have seen him snacking on grass while out in your backyard or on a walk. So, why do dogs eat grass? Is your dog not getting enough food? Could he be sick? Or is it another puzzle springing from weird-yet-normal dog behavior, like “Where do those dog zoomies come from?” and “Why do dogs chase their tails?” It turns out that different dogs eat grass for different reasons. Let’s take a look at the most likely ones.

Most common reasons why your dog is eating grass

1. It’s in their DNA

Though we think of canines as historically carnivorous, they actually evolved as omnivores that would eat whatever was available, including vegetation. Also, the prey animals that our dogs’ ancestors would eat were usually herbivores, so those wild dogs were indirectly consuming plant life. Instinct is a pretty logical answer to “Why do dogs eat grass?” A much less understandable dietary habit, on the other hand, is why dogs like to eat their own poop.

2. A form of pica is behind it

The urge to eat substances other than food is a condition called pica. While pica is a cause for concern in people, it’s usually nothing more than a sign of boredom in dogs. To make your dog’s day less ho-hum, add a few minutes to your regular walks, take him into your backyard or to a dog park for a fetch session, and treat him to a few new chew toys or puzzle toys for those times when you can’t be with him.

3. They just like it

Why do dogs eat grass, specifically? Your pup could simply like the taste or texture of grass, in the same way that we enjoy munching on celery sticks once in a while. “They [may] find it palatable and need to add roughage to their diet,” Katy Nelson, DVM, a senior veterinarian at Chewy, tells Reader’s Digest. Tender spring grass may be particularly delectable to them.

4. They need fiber

If your dog eats a lot of grass, you might want to take a look at his diet. It could be a sign that he isn’t getting enough fiber and, as a result, is seeking out roughage to eat. Just like humans, dogs need fiber to help them digest their food and pass stool regularly.

Cavalier King Charles Spaniel puppy eating grass under a shrubWestend61/Getty Images

5. Their diet is low on a nutrient

While this is less likely to be the case if your dog is eating a high-quality, well-balanced diet, regularly eating grass can be a sign of a vitamin or mineral deficiency. If grass noshing has become a daily habit for your dog, especially if you’ve recently switched dog foods, it’s worth a call to your vet to go over what and how much you’re feeding him.

6. It’s like a natural antacid

Your pup can’t pop a Tums, so when his tummy is upset, he may chew on grass. Bile can build up as your dog’s stomach becomes empty, which can be irritating and uncomfortable. Eating grass can release the bile. Many dog owners have seen this in action after their dog suddenly eats grass like crazy, vomits, and then suddenly appears happier and more energetic. Those pet parents swear this is the answer to “Why do dogs eat grass?” However, at least as many dogs don’t vomit after eating grass as do, so this dynamic clearly only applies to some.

7. Your dog is thirsty

Like most types of vegetation, grass has a high water content. If your dog is eating grass primarily early in the morning or late in the evening when the grass has dew on it, this could be the reason behind it. This may also be the case if he nibbles on grass only on hot summer days. Make sure your dog always has a bowl of fresh water available both inside your home and in the yard.

Will eating grass harm your dog?

Fortunately, nibbling on grass every once in a while won’t harm your pet. That said, many lawns are treated with pesticides, which can be toxic to dogs. And even if the yard in question is chemical-free, your dog may be swallowing intestinal parasites, from feces left behind by other animals, with that clump of grass. So, at the end of the day, a more important question to answer than “Why do dogs eat grass?” is “How do I stop my dog from eating grass?” If your dog is trying to eat grass on the regular, get help from your vet in figuring out what’s behind the behavior and how to end it. And while we’re on the subject, these are the things your dog should never, ever eat.


  • Katy Nelson, DVM, senior veterinarian at Chewy

Christina Vercelletto
Christina Vercelletto covers pets for Reader’s Digest and Chewy’s Pet Central channel. She has 15 years’ experience on staff at national publications, including Parenting, FamilyFun, Scholastic Parent & Child, and Woman's Day and has appeared as a guest on Today, Good Morning America, and The View. Aside from Reader's Digest, Christina regularly crafts content for EatingWell, CNN Underscored, Livestrong, The Knot, Trip Advisor, and other prominent brands. She holds a summa cum laude degree in journalism from Long Island University. Her areas of expertise are lifestyle, beauty, travel, product reviews, and pets.