5 Reasons Dogs Eat Grass And None of them are to induce vomiting

So I'm sitting outside on our patio today and the dogs are outside playing and they start to eat grass and I was thinking to myself, why do dogs eat grass?

I did a little research and The most commonly agreed answer is simply because they like the taste.  It's actually very common for dogs to eat grass and in most cases there's absolutely nothing to worry about.  There are however other reasons your dogs may be eating grass and also some scenarios where you might want to be concerned.  Let’s get into the reasons below.


The Five Reasons

1) Ancestral Roots

From their ancestral roots, dogs are natural scavengers, so they instinctively seek out other things to eat that satisfy their nutritional requirements.  Grass is an excellent source of fiber and as we already learned, they love the taste, so it’s a great fit.

2) Boredom

If you haven't been exercising your dog much recently, they could just be eating the grass out of boredom looking for something to do.  If you think this might be the case, add in some fun play time (fetch, walking, etc) and see if the grass eating subsides. Even if the extra play time has no effect on the grass eating, you both will be much happier having played together.  Win Win.

3) Nutritional Deficiency

The suggestion that dogs that eat grass are not getting enough fiber in their diet is probably the largest myth of these 4 reasons.  A study done by the UC Davis School of Veterinary Medicine showed that there was no indication that dogs fed primarily table scraps or raw food were more prone to grass eating than those on a commercial, nutritionally balanced diet.  Nor was there any indication that dogs receiving less fiber in their diets tended to eat plants more than those getting more fiber.

4) Improving Digestion

This one may be where the belief comes from that dogs eat grass to induce vomiting?  Studies have shown this is not the case, they say less than 10 percent of dogs show signs of being sick before they eat grass. And evidence also shows that this behavior isn’t even that effective when it comes to inducing vomiting. A dog will throw up less than 25 percent of the time after consuming grass, However, us dog lovers know that our dogs are smart enough to self medicate and just because they may not have shown signs of being sick, does not mean that they didn’t actually feel sick.

5) Ridding The Body of Parasites

The same study from UC Davis also offered up another explanation.  It is believed that plant eating played a role in the ongoing purging of intestinal parasites (nematodes) in wild ancestors.  This was observed in wild chimpanzees which eat whole leaves from a variety of plants. The plant material passes through the intestinal tract, wrapping around worms and thereby purging the tract of intestinal nematodes.  Of course nowadays it is known you need to give your dog regular deworming medicine which rids the body of these parasites, but instinctively your dog could still eat grass for this purpose as well.

Causes For Concern

1) Excessive Grass Eating

The most important thing with our pets just like it is with us, is that anything done in moderation is probably fine.  So, as long as your doggies grass eating is not excessive, it’s most likely fine. If however, they are eating grass excessively, that is something you need to pay closer attention to and discuss with your vet.

2) Watch Puppies Closely


Be especially careful with your puppies, especially while teething.  Puppies love to chew on everything like grass, leaves, sticks, etc and ingesting too much of these can lead to blockage and potentially severe problems.

3) Dietary Change

If you recently changed your dog's diet and suddenly they start eating grass all the time or maybe you never saw them eat grass before, then despite the survey mentioned above, it is possible they are no longer getting the nutrients that they need from their food and they're seeking out those nutrients from other sources.  Again, if in doubt discuss the diet change with your vet.

4) Other Plants and Poisons


If your dog likes to munch on plants in addition to grass, there are potentially serious dangers with this. Several common plants are toxic to dogs.  If you added any new plants to your dogs environment, or if you are just not sure if existing plants are toxic or not, the ASPCA has put together a list of toxic plants which you can find here.

And finally, of course if your grass is just been treated with herbicides or pesticides or any kind of fertilizer you wouldn't want your dog to eat the grass immediately after.  Typically it is recommended to keep your dog off of the grass for a couple of hours after treatment, but there should be warning signs either on the packaging or in the paperwork from your lawn care company.


If you do have a dog that vomits every time after they eat grass and you want to stop them from eating it, review all of the reasons above and see if you can find a good way to curb their grass appetite.  It could be as simple as a little extra play time as a distraction, or introducing a few vegetables to their diet, And remember, if your grass has just been treated with any kind of chemical, keep your dog away from the grass for at least a couple of hours.

As always, if you have any concerns at all with something your dog is doing or how they are acting, consult with your vet.

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