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Why Do Dogs Eat Grass?

Does your dog turn into a ruminant at the scent of grass? What compels dogs to graze on lawns and fields? Can you grow dog grass like cat owners grow catnip?

Melvin Peña  |  Mar 29th 2016


I’ve had my dog, Baby, a Bluetick Coonhound mix, for almost two years now, and to my great comfort we’ve finally started settling in to a few predictable routines. I don’t mean establishing feeding or exercise schedules, though we certainly have those. I mean those quirks dog owners notice because they occur with such regularity. For instance, on our evening walk through the neighborhood park, she always pauses by the same tufts of grass and eats a few blades.

“Why do dogs eat grass” is one of the eternally recurring questions that dog owners ask. The simple truth is that there is no satisfying, universally applicable explanation for this snacking habit. You are probably very familiar with most of the standard conjectures in circulation, including:

  • To induce vomiting
  • To cleanse the digestive tract
  • To resolve some nutritional deficit
  • A throwback to wild, feral dog tastes or atavistic lupine habits
  • An obsessive behavioral problem or symptom of an eating disorder
why do dogs eat grass

There is no conclusive answer for why dogs eat grass. (Photo by Towle N/Flickr)

One aspect of this canine quandary that’s not been sufficiently explored are the meta-level questions, by which I mean the questions behind the question. After all, people who spot their dogs developing unusual behaviors may start taking unusual steps to correct them. Let’s look more closely, not for a definitive answer to why dogs eat grass, but rather at how it can cause dog owners to overreact, along with some more recent approaches to dealing with the behavior.

Eating grass: Is it why dogs vomit?

We’re all probably familiar with the hypothesis that grass eating for dogs has an emetic function. It’s long been thought that dogs eat grass in order to make themselves throw up. There is no causal link between grass ingestion and vomiting. Studies have shown what appears to be common sense, that dogs who were showing signs of nausea before eating grass were more likely to throw up after.

Dog owners looking for an answer or remedy to the activity might turn to over-the-counter nausea or upset stomach medications like Pepto Bismol. Because there are so many strengths and formulas, what you have on hand in your medicine cabinet may cause a given dog more digestive upset than it alleviates. Look to the grass itself for an answer: Where does your dog consume grass most frequently? Is it treated with chemicals or fertilizers that could be the source of frequent vomiting?

Grass eating cleans the digestive tract

Another common theory is that dogs who eat grass regularly are attempting to self-regulate or cleanse their digestive tract. This is often coupled with the idea that grass eating is instinctive in dogs, making up for nutritional deficits. The thinking is that there is something — fiber, usually — that dogs are drawn to in grass. A recent Dogster article correctly points out that an age- and breed-appropriate diet, along with regular veterinary checkups, should be more than sufficient to keep dog digestion flowing smoothly.

why do dogs eat grass

Why does my dog eat grass is an eternal question with no easy answer. (Photo via Pexels)

The impulse might be for a dog owner to correct for a perceived lack of dietary fiber on his own. Making radical changes to a dog’s diet is not the solution. Much like using human medications without veterinary supervision or guidance, altering your dog’s food on a whim or offering fiber supplements could wreak more digestive damage than it resolves. If your dog’s grass-eating habits suddenly become extreme or unusual, consult a medical professional before making substantive changes to what your dog eats.

Dogs eat grass because wolves do it

The theory that domestic dogs eat grass is an atavistic impulse, an evolutionary throwback to their lupine ancestry. In slightly more detail, this popular notion is fueled by the thought that wolves and other feral canids developed a taste not only for fresh kills in the wild but also for the contents of their stomachs. This you-are-what-you-eat notion is interesting, but doesn’t supply much substance. I enjoy eating chicken meat, but it doesn’t follow that my taste for domestic fowl causes me to crave worms or dried corn.

Canines of every breed and variety are opportunistic omnivores, meaning that, given the chance, they can and will eat anything, whether it has nutritional value or not. If your dogs spend most of their time indoors, the impulse to grass eating could be driven by simple curiosity or interest in novelty. An increase in time outside, along with increased exposure to grasses, might make the leafy blades less appealing.

Compulsive grass eating in dogs

Some owners see their beloved pets engaging in unusual activities and worry that it signals some kind of behavioral problem. Grass, however, doesn’t usually fall under the purview of rare cases of pica, or ingesting strange or bizarre items, even in dogs. If your dog suddenly develops an appetite for fescue, or any other variety of grass, especially if no such craving existed before, you may want to track your dog’s eating and excretory habits to present a vet with the best and most complete information.

If eating grass only happens occasionally on dog walks, then one useful alteration you could make is to not allow your dog’s pauses to persist. My dog is particularly scent-driven and makes periodic stops along our normal hiking routes to smell or eat grass. In my recent story about dog walking, an expert advised me that it was my indulgence that let the phenomenon persist. She told me that if I stopped stopping when my dog did, she would eventually take the hint. One possible solution is to simply continue walking and not permit your dog’s interest to become an interruption.

A recent alternative: Dog grass

One of the most intriguing developments I’ve noticed popping up over the last several years could be filed under “if you can’t beat it, grow it.” Cat owners cultivate catnip or catmint in their homes and gardens specifically to have a ready supply for their pets. Dog owners are only starting to catch up. Rather than continue wondering why dogs eat grass, a growing number are trying to find safer and cleaner ways to satisfy their dogs’ expressed taste for grass.

why do dogs eat grass

Rather than ask why dogs eat grass, some dog owners grow their own. (Photo via Shutterstock)

As stated above, a very real risk of grass eating in dogs comes not from the grass itself, but from what can be found clinging to it. Landscaping chemical treatments treatments — fertilizers, pesticides, and weedkillers — have been proven to affect not only the lawns and fields they’re applied to, but also surrounding areas. Nearly half of the dogs in one study had traces of lawn chemicals in their urine, despite living in homes with untreated lawns!

How do you address your dog’s grazing impulses?

Landscaping chemicals are only one real risk; in public areas like dog parks or your typical street corner, grass is very likely to have traces of fecal matter from dogs and other animals. Grass with poop on it can carry the eggs of common dog parasites, like tapeworms.

Growing your own dog grass means ensuring that if your dog must eat grass, the grass she consumes is clear of any natural or chemical additives. Does your dog eat grass? Is it a recent development or an occasional indulgence? Have you had any success with providing indoor grasses specifically for your dog to nibble on? Share your experiences in the comments!