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Why does my dog eat grass?

Our question this week was:

She will get excited in the house until you let her out the door so she can eat grass. Why does she eat grass?


Susan Perkel


Hi – thanks for your email. Interesting question and there is a lot of speculation as to why dogs eat grass without any definitive answer. We have an article on this topic. One of our writers did a lot of research on this topic and I’ll share the information she found.

One thing we do know is that dogs are descended from wild canids (wolves and foxes), which ate the entire “kill” when they hunted for food. Since they consumed many herbivores (plant-eating animals), they wound up eating a lot of plants and even berries found in the stomach and intestines of their prey. Interestingly, carnivores tend to go for the stomach and its contents first, so it’s likely that dogs may eat grass because they like it and it was once part of their normal diet.

Then, some believe that dogs may eat grass when they don’t feel well.. Others believe that dogs vomit because they eat grass.

Most veterinarians believe that dogs eat grass simply because they like it, and vomiting just naturally follows. When dogs eat grass, the grass acts as an irritant and causes vomiting.

No matter what the reason, your dog’s “grass” habit is a normal behavior and you need not be concerned about it. A note of caution, however: Take care that your pet does not eat grass that has been treated with fertilizer, pesticides or herbicides. This could cause stomach upset or even worse problems for your dog.

Best of luck!

Dr. Debra

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