Ask A Vet: Why Dogs Eat Grass & What To Do About It


Welcome to our weekly 'Ask a Vet from the SF SPCA' feature on They've enlisted their Co-President, Dr. Jennifer Scarlett, to answer your questions every week. Got a question for Dr. Scarlett? Ask away in the comments!

Q: Hi, Dr. Scarlett! I live in the Mission neighborhood of San Francisco, which means I have to watch my dog closely while we go for walks given the large amount of debris. While I haven't changed my dog's diet, I have noticed that he chews and eats the grass in the boulevards when we go for walks. Why do dogs do this, and are there any risks?
A: Dogs eating grass, also known as pasture-ellosis, is a very common and arguably one of the most contentiously debated conditions in veterinary medicine. Dogs are selective omnivores--like us. Dogs can survive on a vegetarian diet but, if left to their own devices, dogs are anything but selective. They choose to eat meat, garbage off the street, remote controls and sometimes grass. Some folks surmise that in the wild, dogs and their cousins, wolves, eat rodents and other animals whose viscera is filled with grains and grass. Perhaps eating grass is fulfilling a primal need for that roughage.  

Others contend that the dog feels nauseous and the grass is speeding the up the inevitable process of vomiting. I don't know. My dog loves to graze this time of year when the grass is fresh and green and often it isn't associated with any gastro-intestinal upset so, even though she looks more like a cow when doing it, I've concluded that she's really tapping into her ancestral wolf nature when mowing the lawn. As for risks, eating a lot of grass, especially long blades, can ball up and cause intestinal obstruction.

Everything in moderation---if your dog's stomach is upset after eating grass than you'll need to intervene on the grazing.

While we can’t answer all of the questions here, please feel free to ask us during our Friday Twitter Ask the Vet Chat.  If your animal’s problem is of an immediate nature, please call your vet or you can reach the SF SPCA at 415-554-3030 to make an appointment.

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