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Why do Dogs Eat Grass?

Nuala McHugh


Nuala McHugh
Nuala McHugh

Nuala McHugh

Content Writer

Nuala began her writing career when she studied English at Queen’s University Belfast and later earned a Master's degree in PR and Communications.

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Updated: February 20, 2024

Verified by Laura Ward

Laura Ward

Laura Ward

Pet Nutritionist

Laura studied BSc (Hons) Animal Science with an accreditation in Nutrition at the University of Nottingham, before working for eight years in the pet food and nutrition industry.

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Laura Ward

If you are a dog parent, it’s highly likely the question “Why do dogs eat grass?” has entered your head.

Most pet parents have seen their dogs eating grass, sometimes followed by vomiting and then re-eating the grass they just regurgitated. Understandably, you’re left wondering, why?

We’ve heard many myths and reasons as to why dogs eat grass, why dogs eat grass and vomit, and what you should do when your dog eats grass. But what’s the truth behind a dog eating like a cow? And should you be worried if your dog eats grass?

This article will explore the different reasons why your dog is munching on grass and when it’s time to take them to the vet.

Why does my dog eat grass?

Natural Instinct 

Believe it or not, your dog’s ancestors did not eat prepared kibble or fresh vegetables in a bowl for dinner. Dogs in the wild balanced and managed their stomach through meat, bones, and the occasional plant for fiber.

Certain studies suggest eating grass is an instinctual behavior for dogs that evolved from their wolf ancestors. A small percentage of a wolf’s stomach contents contains plant material, so dogs may just naturally eat the easiest plant material available to them. 1 


Although most dogs love being outdoors, if left in the same place for some time, they may get bored and choose to nibble on some grass.

A dog’s day tends to revolve around their human and eating grass could be a form of attention-seeking. If your dog is eating grass, you are likely to pull them away or distract them so as long as this cycle continues, the grass-eating is likely to continue.

If you have an anxious dog, leaving an old shirt with your scent, a new toy, or a fun puzzle while you’re gone could be a better distraction than grass-eating. Ensure your dog gets lots of fun walks, and social interaction to avoid boredom.

Diet deficiency 

If your dog is regularly eating grass, you may want to have a look at their current diet as it could be a sign they’re lacking in a nutrient. Fiber is likely to be the obvious one as their body may be craving more fiber and so they’re sourcing it outside of their dog food.

It’s important to speak to your vet in this case as they will be able to advise whether your dog’s diet needs additional ingredients or supplements. Dogs (and humans) can’t actually digest grass so it’s not the best way for them to get fiber into their diet but they don’t know any different — so we need to help them out.

Generally, a commercial high-fiber diet is a better option than allowing your dog to fill their diet deficiency through daily grass eating.

Your dog may be hungry 

Similar to the diet deficiency, your dog could be eating grass if they are not entirely satisfied with their current diet. 2  

Evaluate their dog food and consider if you are feeding them a complete and balanced diet for their age and breed. If your dog is constantly seeking snacks and eating grass, have a chat with your vet and consider whether your dog needs a different kind of diet.

It’s tasty

Your dog could eat grass simply because they enjoy it. Dogs may enjoy the texture and taste of grass in their mouths. Many dogs are actually grass connoisseurs who prefer to eat grass in the spring when it is newly emerging and has a sweet taste. So, if you notice your dog eats more grass when the sun appears, this is why. 3 

Why did my dog eat grass and then throw up?

Dogs don’t always vomit after eating grass but if they do, it isn’t necessarily a cause for concern, unless it’s a regular occurrence. 

If a dog is experiencing nausea, they may try to settle their stomach by eating grass. Grass can irritate a dog’s stomach linen, which triggers the vomiting reflex.

The vomiting isn’t necessarily bad as it helps to rid the dog’s stomach of the grass and any other substances that may be causing discomfort or irritation. Additionally, eating large amounts of grass can cause a blockage in the digestive system, which can also lead to vomiting.

It can be difficult to decipher if your dog has an upset stomach from grass eating or something else. Generally, if eating grass isn’t an isolated innocent or if your dog is throwing up a concerning amount, you should consult your vet as there could be an underlying health condition or diet deficiency. 

Is it safe for my dog to eat grass?

As much as eating grass isn’t usually cause for alarm bells, it’s probably better if dogs don’t eat grass — there are better options available after all.

Grass is sometimes treated with herbicides and park grass may have been sprayed or treated with something that shouldn’t be consumed

If you’re treating your grass with herbicides, make sure to remove your dog from the area until it has completely dried out.

Grass can also be contaminated by droppings from other dogs and animals. Eating grass contaminated with fecal material can make your dog sick. That’s why it’s important to have your dog on a monthly dewormer and receive regular fecal testing to look for intestinal parasites.

Additionally, many leaves and flowers can be toxic to your dog and even plants such as oregano and bay leaves can cause diarrhea in dogs.

Generally, a nibble on clean grass is nothing to worry about but regular munching or serious vomiting or diarrhea is cause for concern. 4 

Should you take your dog to the vet for eating grass?

If you’re concerned about the quantity or quality of grass your dog has consumed, your vet will be happy to examine your dog for ease of mind.

As mentioned, if your dog is regularly eating grass then this could be a sign of an underlying health issue or diet deficiency. In this case, you should visit your vet and discuss next steps for a diet plan.

If your dog is seriously suffering from vomiting and diarrhea after eating grass, take them to the vet’s as soon as you can. 

How do I stop my dog from eating grass?

  • Regularly exercise your dog to reduce boredom and play interactive games to keep them occupied.
  • Try switching to a different dog food with a high-fiber variety and monitor your dog’s grass-eating habits.
  • Ensure plants and grass are free of chemicals and are not toxic to dogs
  • Keep your dog on a leash when walking through grassy areas
  • Avoid walking your dog or letting them free on grass when they are hungry
Article reviewed by
Laura Ward

Pet Nutritionist

Laura studied BSc (Hons) Animal Science with an accreditation in Nutrition at the University of Nottingham, before working for eight years in the pet food and nutrition industry.

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