Why do dogs eat grass?

Why do dogs eat grass?
Learn about dogs

Theories surrounding why dogs eat grass are endless, could it be boredom, hunger, illness? The definite answer is a mystery.

But don’t worry, you are not alone with the question, with a study reporting that 79% of dog parents said their pet had eaten grass or other plants. It is considered very normal canine behaviour.

A desire to eat bizarre, non-food items (such as grass and plants) is called pica, and it is predominantly an issue in puppies and adolescent dogs.

When they are young it is typically just them trying to cause mischief by stealing things and eating anything in sight. However, it can be a sign that something else is going on.


Your dog’s life revolves around you. You make most decisions for them, when they can go for a walk, when they eat and when they are left on their own.

Understandably, they can get bored and anxious when you are not there or not giving them attention. Tucking into some grass could merely be a way to fill the time.

However, if you are in the company of your dog, maybe they are just craving your constant attention. Eating grass is a way to grab your attention, as they probably know they will get told to stop.

Even negative attention is considered as attention to them, which means you could be unintentionally reinforcing this behaviour. These pooches are much smarter than we think!


This is a very popular theory and is the one that you will have probably heard before. Grass eating is believed to be a method of easing an upset stomach, likely because it is associated with dogs vomiting after eating it. Although this is still very much a possible answer, it is not a proven theory.

It is tricky to tell if your dog just wanted to eat the grass and they now feel ill consequently, or if they felt unwell already and know they will throw up and relieve their stomach by eating grass.

Essentially, it is a cycle, but we do not know where it starts.

Research has found that out of the dogs who regularly eat grass, only 9% were reported to frequently appear ill before eating it and 22% were reported to frequently vomit afterwards. This suggests that eating the grass possibly does not have much to do with trying to soothe an already upset stomach.


Before becoming the loving, domesticated pets we know today, dogs were once wild animals. They would eat whatever was available to them to fulfil their dietary needs, for example, a hunted animal, whose stomach contents contain grass and plants.

Therefore, your pup may still have a taste for grass due to instinct.

Nowadays, our pets do not need to hunt out prey for their evening meal, it is given straight to them in a shiny bowl. Despite this, that instinct to scavenge for food will remain, possibly leading them tucking into your lovely, nurtured garden outside.


Grass is an excellent source of fibre. If you spot that your dog is eating grass, often shortly after their meal, it may be that your dog recognises they need more fibre to aid their digestion.

A 2007 case study followed an 11-year-old Poodle who was vomiting daily for 7 years due to frequently consuming grass. Once he changed to a diet with a higher fibre content it was reported that his sickness came to a halt, showing the importance of fibre in a dog’s diet.


It is possible that your pooch could be trying to self-medicate a problem that you are unaware of. For example, IBS/IBD, gastric reflux and pancreatitis. If your dog is showing additional signs of illness such as vomitingdiarrhoeafatigue, and lack of appetite it is best to consult your vet.


This one is easy. Your pooch just thinks grass is tasty.

Some dogs will only eat specific patches of grass at certain times of the year, such as spring when the new grass arises. This fussiness into what grass they want just adds to the idea that they just enjoy eating it. A grass critic if you will.

Most of them however will just eat any grass at any given opportunity.


In most situations, it is likely nothing to worry about. The grass itself can cause no harm. However, there are a few things to be aware of.

Watch out if your grass is treated with herbicides and pesticides, as these can be harmful if ingested. Also, be mindful of the plants kept in your garden, as there are many common ones that can be poisonous to dogs.

Ensuring your dog is checked for parasites is also important if they frequently tuck into grass, just in case they consume anything harmful that is lurking in the ground. They not only like to eat grass, they like to roll around in it too!



If your dog is oriented around rewards like treats or praise, it is very much possible to train your dog to stop eating grass. Any time they go to eat grass, distract them by changing direction, offering a taught verbal correction or by making them do an already known command such as ‘heel’ or ‘sit’.

If they obey, offer them a treat or praise. This will take time and patience, however, by being vigilant on walks and always going outside with them for toilet breaks you can stop the habit.


If you suspect your dog is eating grass out of boredom, try adding more exercise and play into their routine.

Mental enrichment activities like hiding a toy and getting them to find it using their sense of smell, putting treats inside a puzzle toy, or teaching them a new trick are great options.


As stated, grass-eating can be caused by a nutritional deficiency such as having a lack of fibre. Switching up your dog’s diet to one which contains all the nutritional benefits and ingredients your dog requires in their food will benefit your pooch.

Pure is real, healthy dog food, packed with natural ingredients such as cabbage, carrots, and other vegetables all there to promote your dog’s fibre intake.

There is no definitive answer to why our dogs eat grass, it is another mystery of the canine world we are yet to discover.

There are many different reasons why they could be doing this and often it will not cause any issues. However, sometimes it can cause sickness and vomiting so trying to stop your dog from doing it is recommended.

You may find that this strange habit can be stopped through training, extra mental and physical stimulation and possibly a change in diet. If you think that your dog’s grass consumption is linked to a further issue, seek out advice from your vet.

Dr Andrew Miller BVSc MRCVS

Written by: Dr Andrew Miller MRCVS

Andy graduated from Bristol University in 2010 and sees nutrition as a foundation for our pet's wellbeing and takes a common-sense approach. We are what we eat, and it shouldn't be any different for our pets.

  1. Why do dogs and cats eat grass? Veterinary Medicine, 103, (12), December 2008, 648-649
  2. Pica in Dogs Great Pet Care
  3. Characterisation of plant eating in dogs Applied Animal Behaviour Science, Science Direct, 111, (1), May 2008, 120-132
  4. A high fibre diet responsive case in a poodle dog with long-term plant eating behaviour Journal of Veterinary Medical Science, 69, (7), July 2007, 779-782, doi:10.1292/jvms.69.779. PMID: 17675815

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