Why Do Dogs Eat Grass And Is Eating Grass Bad For Them?

why do dogs eat grass

Why do dogs eat grass? Most owners catch their dogs eating grass at some point in their lives. Dogs could eat grass because they’re bored, hungry, or just because they like the taste. Grass eating isn’t necessarily bad for dogs. But, pesticides and parasites in grass can be dangerous, as can certain common toxic plants. Read on to find out more about why dogs eat grass.

Why Do Dogs Eat Grass – Quick Links

Jump straight to the section you’re most interested in using the links above. Or, keep scrolling for a full rundown. Starting off with – can dogs eat and digest grass?

Can Dogs Eat Grass?

Before we tackle the question of why do dogs eat grass, let’s ask can dogs eat grass? If your dog has thrown up after eating grass, you might think that dogs are unable to digest grass. However, not all dogs are sick after eating grass. In fact, one study found that only 22% of owners surveyed had dogs that were regularly sick after eating grass. This same study also found that dogs who showed signs of illness before eating grass were more likely to vomit after eating it.

These two points suggest that many dogs can eat grass without any problems, and vomiting after eating grass could be the result of another issue.

Why Do Dogs Eat Grass And Throw Up?

Sadly, some dogs do throw up after eating grass. But, this doesn’t mean that grass is causing your dog to vomit. Things like pesticides sprayed on grass and weeds can make dogs sick, as can certain bugs and parasites in grass. Plus, there are some toxic plants that are common in fields and yards that could cause your dog to be sick.

why do dogs eat grass

Some dogs might be sick after eating grass because they are unaccustomed to it. But, another potential cause is that there is an underlying health issue causing your dog to be sick. If your dog eats grass and throws up, it’s a good idea to take them to the vet for a check up. It’s important to identify the cause to ensure you can eliminate whatever is causing your dog to be sick.

If you’ve tested their health and checked there are no toxic plants or pesticides on the ground but your dog is still throwing up, it may be best to prevent him from accessing the grass that he keeps eating.

Why Do Dogs Eat Grass?

Not knowing why dogs eat grass can be a worry for dog owners. Especially if it seems like it’s making your dog sick. Do dogs eat grass because of nutritional deficiencies, or is the actual reason more harmless? Let’s take a look at some possible causes, and some suggestions that have been disproven.


If your dog is eating grass only occasionally, it could be because of boredom. Some dogs won’t pay any attention to grass or plants if they are busy playing, exercising, or training. So, one solution to eating grass could be to keep your dog busy. But, if your dog is pausing exercise, training, or playing sessions to eat, there could be another reason.


Several studies have looked into why dogs eat grass. One found that the behavior was common among all puppies studied, but that more grass was eaten when dogs were hungry. It found that puppies were most likely to eat grass before they were given any other food. Or, a long time after they had last eaten.

If your dog is eating a lot of grass, you should check with your vet that they are getting enough to eat. Alternatively, if your dog is eating grass only in the morning before breakfast, you can try not to let your dog have access to the grass for too long before he’s eaten. Take him out to the toilet, and bring him straight back in to eat.

Fits Naturally in their Diet

Other studies have tackled this issue by looking closer at natural dog diets. One suggests that undomesticated dogs have an omnivorous diet, like humans. This means they eat a wide variety of things, including meat and plants. The instinct to eat plant matter could similarly be found in domestic dogs.

The Taste

Another potential reason dogs eat grass could simply be because they like the taste. After all, dogs like the taste of lots of things we don’t… including their own poop! So, it would make sense that they keep going back to grass because they enjoy the taste of it.

Learned Behavior

One study looked at the grass eating habits of puppies who saw their mother eating grass. It found that puppies with mothers that ate more grass around them were more likely to eat more grass too. This suggests that grass eating could be a learned behavior. Now, let’s look at a couple of theories that have been proven wrong.

Nutritional Deficiency

One suggested explanation that has been widely discounted is that dogs eat grass because of a nutritional deficiency. Many studies have compared different groups of dogs and eating grass. One found that a dog’s diet had no impact on grass eating. This included those eating less fiber.

So, there is no evidence that dogs eat grass because there is something wrong with part of their diet. If you are at all concerned that your dog isn’t getting all the nutrients he needs, speak to your vet.

Self Medication

Another popular theory is that dogs eat grass to self medicate – specifically, to make themselves sick or get more fiber. But, this is another theory that has been widely disproved. Many dogs with no health issues eat grass. And many have no issues like vomiting after eating grass.

One study compared dogs with a standard diet and dogs with a supplemented diet designed to cause loose stools. Those with the supplemented diet were no more likely to eat grass than dogs with the standard diet. This suggests that dogs don’t naturally use fibrous grass to self-medicate. However, if you are ever worried about your dog’s health, take them to the vet. Do not just leave them in the hopes of self medication.

Is Eating Grass Bad for Dogs?

Now we’ve answered ‘why do dogs eat grass’, let’s take a closer look at when eating grass can be bad for our pets. Generally, grass itself is safe for dogs to occasionally eat, as long as they are getting all the nutrients they need from their main diet. But, there are things in and on grass that can harm our dogs.

Pesticides and Parasites

Pesticides are substances used to control weeds and pests that damage plants. But, these sprays and substances are quite often harmful to our pets too, especially if they are ingested. Whilst you may not use any pesticides at home, you won’t know whether there is anything on grass outside of the home. And, even in your own yard it will be hard to control the parasites in the grass and plants.

Toxic Plants

There are lots of common plants that are actually toxic and harmful to our pets. So, if your dog is sick or showing signs of being unwell after eating grass, check if there are any harmful plants in your yard. The best place to do this is the ASPCA website. There is a full list of plants that are toxic to dogs.

If you find any of these in your yard, remove them. And try to avoid areas outside the home if you know there are any toxic plants there. If you know your dog has eaten a toxic plant, call your vet straight away.

Other Problems

Because eating grass itself is generally safe for dogs, if your dog is sick after eating grass you should check with the vet that your pup has no other health issues. Vomiting is a symptom for many other health problems. But, your vet will be able to analyse and check your dog for other symptoms to narrow down the possibilities.

How to Stop Your Dog Eating Grass

Although many reasons why dogs eat grass are harmless, some dogs are sick after eating it. If this is the case for your dog, you may want to stop them from eating it. You can do this by identifying the cause of grass eating.

The Labrador Handbook by Pippa Mattinson

If your dog is eating grass because he is bored – try to play interactive games with him, or exercise him more. If he is eating grass because he is hungry, speak to your vet about increasing the amount of food you give him, or restrict his access to grass until he has eaten in the morning.

Preventing access to grass is a good way to ensure your dog isn’t eating it excessively. You can also try to distract him from eating grass with toys or other treats.

Why Do Dogs Eat Grass Summary

Does your dog eat grass at home? Why do you think your dog likes to eat grass? Make sure to share your experiences in the comments below.

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References and Resources

The Labrador Site Founder

Pippa Mattinson is the best selling author of The Happy Puppy Handbook, the Labrador Handbook, Choosing The Perfect Puppy, and Total Recall.

She is also the founder of the Gundog Trust and the Dogsnet Online Training Program 

Pippa's online training courses were launched in 2019 and you can find the latest course dates on the Dogsnet website


  1. My 2 border collie x dogs (lab/kelpie) prefer to eat the new tender grass that grows along the fence line or garden border edges of my yard. This grass does not get mowed regularly and they eat it when it is about 6” long, at light green colour. They will do this most nights just before bed time. I believe it would provide vitamin c and fibre to cleanse the bowel. It also makes them check the borders for smell so that they know if there are any intruders into their territory over night. They identify threats (rats/wildlife) and will wake during the night if they hear any activity related to these scents they identify on their nightly patrol. I guess that’s why they are called border collies. They never eat grass on walks or at the beach or in unfamiliar areas. Maybe they eat it as this tender grass is also attractive to the intruder species and it this discourages then entering to feed.