Why does my dog eat grass?

            Why does my dog eat grass? That’s an age-old question with almost as many answers are there are dog breeds. While doing research for this article I came across several viable answers. And if you have a dog that eats grass, you’ve probably heard most of these.

            It’s a popular belief that dogs eat grass because they are experiencing nausea. This theory doesn’t really hold up because not every dog that eats grass vomits afterwards. In the studies that I read, it seems that only about 25 % of dogs showed signs of nausea before eating grass and vomited after they ate it. So, it would seem, for them, eating grass does help them get rid of whatever is upsetting their stomach. A poor diet is another popularly held myth as to why Fido eats grass. But, not every dog that eats grass is consuming a diet that is lacking in quality nutrients. Pica, a condition that causes dogs to eat non-food items also makes the list. But, who says that grass is a non-food item?  It is also thought that dogs may eat grass to aid in digestion because it’s high in fiber. This theory assumes that dogs can make the connection between how they’re feeling and which plants to eat to feel better. I’ve also heard that dogs have no way of clearing mucous from their throats and eating grass helps move it along. I would add boredom to the list as well. If a dog has little to no enrichment in their environment they will play with or chew whatever is available to them. This could lead to grass eating, poop eating, and a host of other OCD behaviors.

            The above are probably true for some dogs, but your dog may have her own reasons for eating grass. Of my five most resent dogs there were two grass eaters. One, a yellow lab, which I suspect is part goat, has eaten grass all his life. Not the type used as lawns, but rather the kind that you would find growing in pastures and on road sides. The kind cows and horses like. he only vomits when his stomach can’t digest it completely. But, usually it will pass through his digestive tract within a couple of days. He is fed a high quality commercial diet supplemented with dehydrated raw food. I think he eats grass because he loves the way it tastes! Have you ever chewed on a piece of hay? It has a sweet green taste that I suspect he likes.

My other grass eater, a chocolate lab, only ate grass if the older dog was eating it. If I was out with just him, he never went near it. For him, eating grass was a learned behavior that he picked up from watching his big brother. He only nibbled a piece here and there and never vomited after. None of my dogs have ever eaten the lawn[1]. As puppies, they would pull up clumps of grass, but spit it out or run around playing with it. They didn’t actually consume it. I’ve also seen dogs just slide grass through their teeth as if trying to pull it up, but not biting onto it hard enough to remove it from the ground…maybe they’re using it to floss? Dogs have evolved to be omnivores. And like most omnivores they like many different foods, including meat, dairy, grains, fruits, and veggies. Grass technically falls under the grain category, but we always refer to it as a “veggie snack” in our house.

 So, why do I think dogs eat grass? Mostly because they find it rewarding in some way. Dogs live by very simple rules. And number one on the list of rules is, ”If it taste’s good, eat it!” They don’t stop to rationalize whether it’s going to make them vomit or if it’s bad for them. Long before there was commercial food, dogs ate what they could scavenge or whatever scraps their owners tossed their way. It was very common for these things to make them vomit, hence that old saying, “Sick as a dog”. I believe that a lot of dogs eat grass just because they like it. For other dogs, it might be an OCD[2] behavior or a symptom of a deeper issue. If your dog’s grass habit is extreme, an everyday occurrence causing him to vomit or have digestive issues, or if you suspect that it’s due to some dietary deficiencies, please discuss it with your vet or a pet nutritionist so they can help you rule out any underlying health problems. Also, please be aware that consuming large amounts of grass can cause a blockage in their gut which left untreated could be life threatening.  For most dogs though, a little grass in moderation is fine…        


[1] Eating the grass on lawns should always be discouraged because of the chemicals that may have been used in fertilizers and pesticides.

[2] If you suspect your dog has some uncontrollable OCD behaviors, please contact a trainer that uses force free positive reinforcement methods.