No walk around the neighborhood is complete without my dog Lulu eating grass. Even on a full stomach, she likes to hunt for the perfect blades and chew away. Left unattended, I’m sure she could mow down a small lawn. Since lawns today have any number of herbicides and pesticides, many pet parents wonder if it's OK to let their dogs eat grass.

Here's what the experts say about these grass-eating habits.

It’s yummy: It's normal for dogs to chew on the green stuff because they like the taste of grass, says Dr. Jennifer Monroe of Eagles Landing Veterinary Hospital in Georgia. Some pooches even develop preferences that range from fresh leaves to drier weeds or even a particular species of grass. What they cannot discern is whether grass has been chemically treated. Use caution when walking on a neighbor’s lawn and stick with greener products in your own yard. Monroe recommends nontoxic treatment options.

“You do have to be careful if you have a dog that is a chronic grass eater,” she says. “We do have a lot of clients who bring pets in for vomiting and wonder if it’s from something the yard was treated with.”

Nutritional deficiency: Most commercial dog foods offer a balanced diet, so many experts say its unlikely that your dog isn't getting the nutrition he needs from his dinner. Instead, dogs with certain intestinal diseases don’t necessarily digest food properly and have trouble absorbing minerals, which can lead to grazing, says Monroe. Anemia and bleeding in the gastrointestinal tract also cause dogs to eat dirt.

dog eats grass Some dogs eat grass because they need to throw up. (Photo: smerikal [CC by-SA 2.0]/Flickr)

They are trying to induce vomiting: When dogs are eating something that doesn’t agree with them, they often have an upset stomach and eat grass to induce vomiting. If eating grass causes your dog to vomit twice a week or more, call your veterinarian because there could be another underlying health issue. She also recommends a visit if there is any doubt that your dog may be ill; better safe than sorry.

Some dogs nibble the lawn and are fine, while others are always eating grass and vomiting. It may just be the grass tickling their throat and stomach lining that causes them to vomit, says PetMD, or it could be something more serious. That's why it's key for dog owners to make sure their pets aren't sick. Keep track of how often your dog vomits and let your vet know.

Instinct: One theory is that this unusual dog behavior is just instinct. Dogs in the wild are natural omnivores who eat meat and plants, so domesticated dogs naturally gravitate towards plant material too, says Purdue University College of Veterinary Medicine. Another theory is that wild dogs would eat plant material in the stomach of their prey, so they developed a taste for it.

Behavioral issues: Dogs can develop obsessive-compulsive disorder (OCD) regarding the grass. (I suspect that my Lulu falls into this category. She’s pretty determined during those lawn-gobbling excursions.) In the majority of cases, Monroe says this is no reason for concern. To correct the behavior, she recommends reducing your dog’s grazing time.

Basket muzzles restrict grass guzzling, too. In severe cases, she recommends consulting a certified veterinary behaviorist for advice. Otherwise, let them stop to smell — and chomp — the greenery.

“If not they are not vomiting and not destructive, I say let them enjoy it,” Monroe says.

Editor's note: This story has been updated with new information since it was first published in October 2013.

Why do dogs eat grass?
Pet parents want to know why their dogs eat grass and if it’s OK. Here's what the experts say about these grass-eating habits.