Why do dogs eat grass?

There are lots of reasons why your dog might be eating grass, with just as many myths and theories about where this behaviour comes from. But one thing vets and experts can agree on is that a dog eating grass is perfectly normal behaviour, as long as it’s only in small amounts.

Is my dog eating grass for food?

Dogs are natural omnivores. Historically, eating plants like wild berries and grass would’ve been part of their normal diet. These days balanced commercial diets take care of all your dog’s nutritional needs, so there’s usually no nutritional reason for dogs to eat grass. Dogs on home-made diets, such as those that include only meat, may however be eating grass as a way to get much needed fibre into their diet. We recommend switching to food that is more nutritionally balanced and ensure they get all the goodness they need.

Is it harmful for dogs to eat grass?

Eating small amounts of grass is still a small part of a dog’s natural diet and shouldn’t do much harm. However, excessive amounts can irritate the stomach, causing your dog to throw it all back up. There’s even a theory that dogs eat grass to deliberately eat grass to make themselves to throw-up when feeling nauseous or ill (such as if they have worms). There’s evidence of various wild animals self-medicating in this way, so there might be some evolutionary basis for this behaviour in dogs too.

So while grass itself is largely harmless, you should still keep a watchful eye on what grass your dog is eating – for example, roadside grass is likely to be affected by pollution and petrol fumes.

Avoid using weed killer or other chemicals in your garden so that your dog doesn’t ingest any with the grass. And there are several common garden plants that can grow in and alongside grass that are toxic to dogs that you may also need to keep an eye out for.

Related blog: Which plants are dangerous for dogs?

When do dogs eat grass?

Dogs are most likely to eat grass during spring and early summer when the new shoots have shot up. Their fresh fragrances and sweet sugars make them intriguing and appealing to your dog, adding a bit of sweetness to spring walkies. Some dogs can develop a real taste – perhaps even a habit – for grasses. But for most it’s simply an occasional curiosity.

Some dogs will eat grass out of boredom if they’re left alone or confined to a small area for an extended period. This is especially true for dogs who are left outside in the garden all day. Puppies also like to chew and bite everything in sight, including grass, but this is something they should soon grow out of.

Related blog: What to do if your puppy is biting or chewing

It could also be that your dog is just hungry. It’s worth checking that you’re feeding your dog the right amount of food at the right time, splitting out meals to different times of the day if necessary to keep them feeling fuller for longer.

3 thoughts on “Why do dogs eat grass?”

  1. Our Border terrier is a big fan of tender young wheat-grass- and also young oil-seed rape leaves. While I have never seen any of the latter come back up, it does make him somewhat flatulent… Our old Lurcher was so fond of blackberries that she would pick them herself- albeit carefully!

  2. This is an interesting and informative article and explains a bit about my rescue dog Jack’s grass eating behaviour, which in spring is a regular occurance. We call it ‘sicky saturday’!.
    Although not great grass eaters I feel sure my previous two labradors would have fared well in autumn in the wild. They took advantage of all blackberrying opportunities sometimes spending far longer than me carefully picking the more accessable ones! They also loved nuts, particularly hazelnuts and chestnuts. We had no problems with either dog except for having slightly darker colour poo!


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