Why Does My Dog Eat Grass?

If you let your dog outside in the back garden or if they are running around a field on a walk, you may suddenly catch them eating grass and panic.

Is that safe? What if there is something on the grass which could harm them? Why are they doing it?

The truth is that there may be a few reasons why your dog is eating grass, and you are not alone in having a dog that does this.

It is quite common for dogs to eat grass, and has even been observed with wild dogs. If they eat it gently and calmly, they may simply enjoy the taste, but there are certainly other signs to look out for.

The name for the disorder characterised by eating strange non-food items is pica. Your dog can choose anything to eat, from paper and toys to your slippers, so grass is actually pretty harmless in comparison.

Dogs can eat foreign objects out of boredom, but it can also be a sign that they are lacking a nutritional, balanced diet.

If your dog has chosen grass as their non-food object to eat, some vets argue that it is normal behaviour for them (and that you’re lucky in comparison to the other things which dogs have eaten over the years).

In studies, when given plants that are safe to eat as well as ordinary food, dogs chose to eat grass occasionally of their own free will, and it is thought that the majority will do it at some point.

Why a dog may eat grass


Some people assume that dogs eat grass to relieve upset stomachs, which is a common old wives tale according to some vets.

Do dogs eat grass to relieve their stomach make themselves sick, or are they sick because they ate grass? Studies show that less than 25% of dogs vomit after eating grass, and 10% of dogs show signs of illness prior to eating grass. So – the answer is maybe neither.

It is thought that this concept comes from the idea that cats eat grass in order to encourage furballs and a good digestive system.

Yet, it could well be a behaviour that is inherited or taught and is natural instinct, developed from the wild with dogs who have no other source to make them better. They could be drawn to the grass because it is not easily digestible or because it will create an odd sensation in their throat, encouraging them to be sick.

Improving digestion

Like a lot of smaller animals, dogs need roughage in their diets to improve digestion and ensure everything runs smoothly. A lack of roughage affects a dog’s ability to digest food and pass it out effectively, so grass may actually help their bodily functions.

After all, the grass is a good source of fibre.


We aren’t suggesting that you aren’t feeding your dog, but it could be the case that they haven’t eaten as they are having an off day. Humans do this, too.

Ever heard of ‘Bilious vomiting syndrome’? It is bile-induced inflammation of the stomach and is most common in dogs who have gone all night without eating.

There have been links between this condition and grass-eating in the past, especially if the said dog goes for a long period without eating in between regular meal times.

Nutritional deficiency

Pica often stems from a diet deficient in nutrients, vitamins, or minerals.

There have been cases where a dog’s diet was changed to include more fibre if they were daily grass eaters, and in response, the dog often stopped eating grass altogether.

This suggests they may have been lacking the necessary nutrients. Dogs are not thought to need fibre in their diets as a must (unlike humans), but it is thought that it has the same effect on humans. That is, to improve colon health, digestion and improve conditions such as diarrhoea and constipation.

This can be the remedy with all forms of pica according to other studies into the condition. It may be instinctive for your dog to think that if they aren’t getting what they need from the food available, they have to find it elsewhere – and they aren’t limited in what they may try.

Water intake

Most plants have water value. We know this from the ones we eat. So it could be the case that your dog is thirsty and needs a drink.

Dew and moisture can also sit on the grass, which your dog may be attracted to. You should always ensure you have water available for your pet, especially if they are outside and might be hot or exhausted after exercise.


We haven’t eaten any ourselves, but it is believed that grass tastes rather fresh, natural and fragrant. Some dogs may like this and there is nothing more to it.

In Spring and Summer months, it is fresh and green so more appealing. And it certainly makes a change from meaty food. We aren’t saying they necessarily want to become vegans, though.

My dog is eating grass frantically!

This is not just an occasional nibble and off they go. Your dog is tearing chunks out of the ground and swallowing the grass. As we said in the introduction, this can be when you need to start acting.

When this is happening, it is thought to definitely be a sign that something is up with their tummy and they want desperate relief. While eating grass is common, many dogs will try to find a nice green patch that is tasty, but dogs in a hurry may eat any kind.

As mentioned above, grass may tickle a dogs throat and stomach to encourage sickness. Dogs who are desperate could hunt out the rougher stuff because of this. They may also be ingesting other things such as plants or mushrooms without even realising which can be a worry.

But take a step back before you rush immediately to the vet, and think about other factors as well. Are they displaying further signs of illness which explains this? Or are they going to the toilet regularly and eating food normally?

If everything else seems fine, keep an eye on them anyway, but do think about if you have told them off for eating grass in the past in a panic. You have? Well, they could well be being cheeky and eating voraciously when your back is turned knowing that it will end up with them being given attention (even if it is negative attention).

Should I stop my dog from eating grass?

Although most experts agree that your dog eating grass is not a harmful trait, it can be worth bearing in mind that there could be things on or in the grass which are harmful. From pesticides to slugs and poisonous items to plants, watching your dog suddenly tear a chunk of grass from the earth should alert you to keep an eye on further behaviour.

Ensure they are protected against lungworm (which is commonly passed on by slugs and snails) by using a regular worming treatment. These come in the form of tablets or spot-on treatments, and while they can’t prevent lungworm infection, they can allow a dog’s body to manage the parasite.

Also read up on the effects of grass seeds on dogs, which is particularly dangerous in longer grass. If your dog does have something stuck in its throat, it may show symptoms of reverse sneezing.

What can I do about my dog eating grass?

Think about why your dog may be eating grass. If you think they’re bored, it could be good to incorporate playing and activities into their walks to distract them.

Changing their diet can be the next step, so you can switch to a better dog food packed with nutritional value, particularly if it contains more fibre. Also, look at moisture content and ensure they always have drinking water available and accessible to them.

Think about whether they may be hungry, and possibly feed them before you go out or go later in the day so they are not as hungry as they would be in the morning before breakfast.

If they seem to enjoy the taste with a leisurely graze, you could look into introducing vegetables and greens into their diet along with their ordinary food, adjusting the portion sizes accordingly.

Dogs eating grass: When to seek veterinary advice

While most cases are harmless, you should speak to a professional if:

  • Your dog is only eating grass and is avoiding normal food and treats
  • The eating becomes excessive
  • They are constantly eating grass and vomiting afterwards
  • Your dog appears unwell in other ways on top of eating grass

Remember that your vet is always there to give advice when you need it, so if you are worried and want to explain the whole story to them to see how they feel, you can. They may suggest you bring in your dog for a checkup to ensure everything else seems okay.