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Why do dogs eat grass – four reasons from a vet

Why do dogs eat grass
(Image credit: Getty Images)

Have you caught your dog mowing your lawn? Does your puppy vomit up strands of grass after a trip outdoors? If so, you’re not alone – eating grass is a common canine behavior that leaves many pet owners puzzled.

Interestingly, we don’t know exactly why some dogs choose to eat grass and others don’t – and our dogs can’t speak up to give us any insight. However, veterinarians and veterinary behaviorists do have some theories on what makes your dog decide to start grazing.

To help get to the bottom of your dog’s vegetarian habit, consider these four common reasons why dogs eat grass.

Eating grass may be a sign of nausea

Many pet owners have heard that a dog will eat grass to soothe an upset tummy – and this may in fact be true. Many dogs will seek out grass, dirt, or other non-food objects when they are nauseous. Veterinarians have hypothesized that the grass may help settle the stomach, or may simply encourage vomiting to get the offending material out.  

If your dog is eating grass due to an upset stomach, you may notice other symptoms of nausea such as drooling, lip licking, exaggerated swallowing, not eating, or vomiting. If your dog exhibits these symptoms, it’s important to see your veterinarian for further evaluation.

Although nausea can sometimes occur due to simple gastroenteritis (or inflammation of the GI tract) or from dietary indiscretion, other causes of nausea can be much more serious, so it’s important to have the problem evaluated and treated.

Gastrointestinal disease can lead to eating grass

Maybe your dog isn’t exhibiting all the symptoms of nausea, but that doesn’t completely rule out a digestive problem. Some dogs may choose to start eating grass if they are experiencing issues such as intestinal parasites, enteropathy, gastritis, gastroesophageal reflux (also known as GERD or heartburn), or other conditions affecting the stomach and intestines.

However, it is important to remember that eating grass is not always a symptom of an underlying problem. In some cases, dogs just eat grass because they like it. But if your dog exhibits other signs of gastrointestinal disease, such as changes in appetite, nausea, vomiting, changes in stool quality, or abdominal pain, it’s definitely time to see your veterinarian for an examination.

Many pet owners worry that eating grass or dirt is a sign of a dietary deficiency but, fortunately, this is usually not the case. Studies have shown that eating grass and dirt rarely correlates to any kind of nutrient deficiency or excess. If your dog is eating the best dog food that is age-appropriate and also complete and balanced, then it is highly unlikely that his diet is contributing to his love of grass.

If you are concerned that your dog’s diet may be inadequate, you can learn more about how to choose an appropriate dog food or consult your veterinarian – they are your best resource to recommend a dog food that will be a good fit for your dog’s individual needs.

Why do dogs eat grass

(Image credit: Getty Images)

Dogs eat grass as an attention-seeking behavior

Sometimes when our dogs perform weird, gross, or unusual behaviors, we inadvertently reinforce the behavior by making a big deal out of it. When your dog eats grass and you react – whether that reaction is scolding, surprise, concern, or simply trying to distract him away – he learns that eating grass is something exciting and a good way to get you to pay attention to him.

Attention-seeking behaviors are especially common in puppies. They also tend to explore the world through their mouths – another reason why your pup may find it fun and interesting to eat grass.

Eating grass is not inherently harmful unless your dog is eating a lot of it. So the best way to deal with eating grass as an attention-seeking behavior is to simply ignore it. If you don’t make a big deal out of the problem, your dog will soon learn that this is not an effective way to get your attention. If necessary, you can also gently lead your dog away from the area to discourage grass-eating – just be sure to stay calm and avoid too much interaction with your dog while you do it.

Maybe it just tastes good

Eating grass is just a normal behavior for some dogs and it isn’t necessarily harmful. We don’t know exactly why they do it – maybe it is an instinctual behavior or maybe it just tastes good!

Although grass eating can sometimes lead to vomiting, diarrhea, or blades of undigested grass in the stool, this usually isn’t anything to worry about as long as it only happens occasionally. Just make sure your dog does not eat grass from areas treated with fertilizers or pesticides and keep an eye out for any poisonous plants that could cause more serious health problems.

If your dog’s grass eating is more frequent or is accompanied by other changes in health or behavior, consult your veterinarian to find out whether an underlying medical condition could be contributing to the issue.

Why do dogs eat grass? It’s a mystery

The truth is, we still don’t know exactly why some dogs like to eat grass. Some dogs will eat grass their entire lives for no identifiable reason and without any ill effects. However, eating large volumes of grass or clods of dirt can lead to digestive problems for your dog, so it’s a good idea to keep a close eye on this behavior.

If your dog’s grass-eating behavior is new or worsening, or if it is accompanied by other changes in health and behavior, then it may be worthwhile visiting your veterinarian to ensure there is no cause for concern. 

Otherwise, your dog is free to continue his grazing behavior – and you’ll have less lawn mowing to do this summer.

Elizabeth Racine, DVM

Since obtaining her doctorate in veterinary medicine, Dr. Racine has worked exclusively in small animal general practice. Her work has been featured in blog posts, articles, newsletters, journals, and even video scripts.