Why do dogs eat grass?

All of us have seen our dogs happily grazing in our gardens, especially enjoying the uncut long grass on the edges. Just to see a pile of slimy grass on the living room carpet moments later.

So why do our dogs eat grass?
There is no certainty why dogs eat grass. Many studies have been carried out to link grass eating with illness (to induce vomiting), vitamin or mineral deficiencies and lack of roughage in the diet, but none of the studies found any significant evidence. Most say it is very normal behaviour for dogs.

There are three main theories:

  • Instinct. Dogs are omnivors, meaning they eat meat and plants. Although your dog shouldn’t need extra nutrients if he is eating a balanced diet, he might eat grass for its nutritional value.
  • Dogs eat grass to vomit. Many times you will note that your dog vomits after eating grass. But, veterinarians still aren't sure if dogs eat grass because their stomachs are upset or if their stomachs get upset after they eat grass. However, many vets suspect it's because their stomachs are upset, because dogs who are energetic and perky seem to be able to eat grass without getting sick afterward. It seems likely that there is something in grass that does stimulate the urge to vomit. If your dog eats grass then vomits and seems fine, he’s probably taken care of whatever was bothering him. If he keeps retching and is unable to throw up or keeps eating grass and carries on vomiting, you should take him to the vet.
  • Some dogs eat grass because they like the taste.

Is it harmful?

  • Grass is harmless unless consumed excessively.
  • Don’t let your dog eat grass that has been treated with pesticides, fertilisers or any chemicals. Most lawn-care products will indicate whether or not they’re safe for pets. Even if using “pet friendly” products you should keep your dog away from the grass soon after chemicals have been applied. Most products break down fairly quickly, but they can be quite dangerous if your dog eats them while they are fresh.

-(Hilda Geyer/Health24, July 2009)

Reviewed by veterinarian Dr Katja Bier.

Read more:
Water: your dog's life line
Pet Health Centre
Ask our Dog Behaviour Expert

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