Why Do Dogs Eat Grass?

It is surprising how little we know about the quirks of our canine companions. Eating grass is a great example: Why do they do it?


In truth, no one is sure, although there are some intriguing suggestions that seem reasonable. Here are the three that seem the most plausible, for you to make up your own mind.

#1: Wild Origins

There is a growing trend towards feeding a 'raw diet'. This is a move away from highly processed foods to offering a balanced diet of raw meat, bone, and vegetables. The idea being to more closely mimic the diet eaten by dogs in the wild.


What has this to do with grass?


When a wild dog makes a kill, say a rabbit, he doesn't neatly nibble away the breast and thigh muscles (the equivalent of eating best chicken breast) but gobbles down most of the animal. This include fur, skin, and….gut contents.


What do rabbits eat a lot of? Grass!


Yes, that's right. Wild dogs take in a lot of herbage and grass which is inside the gut of their kill. One possible explanation as to why dogs eat grass, is that they crave extra roughage, which is lacking in some processed foods.

#2: Nature's Medicine

Most pet parents are only too familiar with the aftermath of eating grass - the dog is sick.


Another thought is that grass acts as a natural purgative, to rid the stomach of undesirable substances and cleanse the system. The fly in this jar of jam is that not all dogs do vomit after eating grass, in fact it's thought only around 25% of dogs regularly vomit after dining on the green stuff.


Other suggestions are dogs are instinctively drawn to grass as a means of easing stomach ache, balancing dietary deficiencies, or as an anti-worm purgative.

#3: Abnormal Cravings

In the same way that pregnant women may crave unusual foods, so some dogs crave unusual food. Indeed, dogs take things a step further and develop 'pica' which is a desire to eat non-food substances.


Pica is a well-recognized phenomena, but again is one of those things we know have little explanation of why it occurs. Contenders for the best explanation include:

  • Dietary deficiency: To correct a nutritional deficiency in the diet

  • Anti-parasite treatment: To purge worms or larvae from the stomach

  • Exploratory behavior: In a similar way puppies chew anything and everything

  • Learned behavior: It becomes a habit

  • Hunger: Puppies especially will exhibit pica if they are underfed

  • Stress: The repetitive action of chewing is very soothing to some dogs.

Should You Worry if your Dog Eats Grass?

Probably not.

The chances of your dog coming to harm are slim indeed. That said, eating lots of long grass can lead to a tangled blockage in the bowel and is best avoided.


Since the cause is not known, grass eating is difficult to prevent but it's worth eliminating the obvious first, by:

  • Deworming: Regularly deworm your dog

  • A good diet: Feed a good quality balanced diet that includes some fiber

  • The right amount: Don't under or over feed the dog


However, if you are concerned about your dog's habits or they show signs such as increased thirst, weight loss, or altered appetite then always consult your vet. Remember, there is an outside chance that eating grass is helping to alleviate stomach ache or nausea, so it could be the dog's way of asking for help!

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