Why does my dog eat grass?

If your dog eats grass, is it because they are sick, do they need to vomit, or could there be some other reason that they are frantically munching on the lawn? If you’ve observed this seemingly strange behaviour then you may be wondering why your dog does it, whether they’re ill or if it’s a normal behaviour.

Why does my dog eat grass?

Eating grass is a common and natural behaviour for dogs.

  • Dogs eat grass for a number of reasons, but for many it could just be that they enjoy its taste or texture
  • Eating grass is not necessarily linked to health issues or dietary deficiencies
  • For some dogs, chewing grass could be a sign of boredom
  • Contact your vet for advice if your dog:
    • Eats grass but not their food
    • Eats excessive amounts of grass
    • keeps eating grass and then vomiting
    • Appears unwell 

Reasons your dog may be eating grass?

There are several reasons why your dog could be eating grass. You may have heard that dogs eat grass to make themselves sick, or that they do it because they are lacking certain nutrients, but this isn’t always the case.

Dogs may eat grass because:

  • They like it
    We tend to think of dogs as mainly eating meat, but it’s normal for them to eat both meat and plants. Eating grass seems to be more common between April and August, and it’s possible that the weather and season may change its taste, texture or smell
  • They’re bored
    If your dog isn’t getting enough mental stimulation then they may turn to behaviours such as eating grass, digging or chewing
  • They need to be sick
    It’s a widely held belief that dogs eat grass either to make themselves sick or to help settle their stomachs. However, a survey of around 1,500 dogs in 2008 found that fewer than 1 in 10 dogs showed signs of being ill before they ate grass, and only a quarter were regularly sick afterwards. Although some dogs do vomit, it doesn’t always happen, and this research suggests that it’s actually more common for dogs not to be sick after eating grass
  • They need fibre
    Some researchers have suggested that some dogs may eat grass to try and get more fibre into their diet. In one case reported by researchers, a dog had regularly been eating grass and being sick for seven years, but stopped this behaviour when put on a high fibre diet. If you are thinking of changing your dog’s diet then always speak to your vet first
  • It helps get rid of parasites
    Other researchers have suggested that some dogs may regularly eat grass to help flush out any parasites that may be in their intestines. The undigested grass could help to clean out the gut by wrapping itself around any parasites and removing them as the grass passes out of the digestive tract

Is it normal for dogs to eat grass?

Yes. A survey of 1,500 dog owners found that nearly 70% said that their dogs ate plants every day, or at least once a week. This behaviour was found to be especially common in younger dogs. Dogs are omnivores, so eating both plants and meat comes naturally to them; and it’s not just pet dogs that eat grass either, as grass eating has been observed in wild dogs too.

Should I stop my dog from eating grass?

Eating grass is a normal behaviour for dogs. It’s unlikely that they’ll get much nutrition from it, but for an otherwise healthy dog that is regularly wormed, eating grass every now and again is unlikely to be something to worry about. However, dogs should never be allowed to eat grass that has been treated with fertilisers, herbicides or pesticides. There’s also a risk that slugs or snails that have travelled over the grass could infect your dog with lungworm. If your dog is eating grass excessively, is regularly sick, or is showing signs of other health issues, then you should always speak to your vet.

Find out more about lungworm.

What should I do if my dog eats grass?

Eating grass every now and then is natural for many dogs, but if you are concerned about your dog’s health, or worried that their grass eating is excessive, then you should contact your vet for advice.

How can I stop my dog eating grass?

If you’re worried that your dog is eating too much grass, or is doing it too regularly, then it’s possible that your dog may have an underlying health issue, or that you need to review their diet. In these circumstances, it’s always best to do this with the help of your vet. Some dogs may eat grass because they are bored, so providing them with more mental stimulation and physical exercise could help. You could try giving them puzzle feeders, playing obedience games with them or taking them for longer or more stimulating walks.

My dog is eating grass, when should I contact my vet?

Eating grass occasionally is normal for dogs, but you should contact your vet if your dog:

  • Shows other signs, such as not eating the food you give them, seeming tired or having diarrhoea or constipation
  • Eats grass obsessively
  • Keeps eating grass and being sick

If you're ever concerned about your dog’s health then it’s always best to speak to your vet for advice, or speak to a Kennel Club Accredited Instructor if you're concerned about their behaviour.  

Find out more

Find answers to some of the other most commonly asked questions on our 'why does my dog?' hub, such as:
  • Why does my dog eat poop?
  • Why does my dog shake?
  • Why does my dog stare at me?
  • Why does my dog follow me everywhere?
  • Why does my dog lick me so much?
  • Why does my dog lick my feet?
  • Why does my dog sneeze so much?
  • Why does my dog smell of fish?

Think your dog may be affected?

If you're worried about your dog's health, always contact your vet immediately!

We are not a veterinary organisation and so we can't give veterinary advice, but if you're worried about any of the issues raised in this article, please contact your local vet practice for further information

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If you're looking for a vet practice near you, why not visit the Royal College of Veterinary Surgeons' Find a vet page.

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