Why Does My Dog Eat Grass?

Analysis by Dr. Karen Shaw Becker

Story at-a-glance

  • Most dogs eat grass occasionally and some do it more often; there can be a few reasons for the behavior
  • Dogs who munch on grass may be trying to relieve digestive upset, they may also be seeking certain nutrients their diet isn’t providing
  • If your dog regularly ingests large quantities of grass, make an appointment with your veterinarian, and in the meantime, consider upgrading his diet to help provide him with all the nourishment his body needs

Most dogs eat grass from time to time, and some make it a regular habit. Grass eating falls into the category of curious canine behaviors that seem harmless enough, but many pet parents are concerned there may be an underlying problem with their dog's health.

Reasons Dogs Eat Grass

The fact is that grass-eating, a behavior some classify as "pica" — the ingestion of non-food items — is quite common among not only domestic dogs, but wild canines as well. And while grass is not a primary food source for dogs, it is for other species, so while I don't classify nibbling grass as pica, I do recommend owners evaluate their dogs' intestinal health and nutritional status, if the behavior becomes obsessive.

The activity can be a sign of boredom or a way to pass the time for some dogs; for others, it's a fun and rewarding behavior. However, there are also certain health-related reasons dogs eat grass:

To relieve gastrointestinal (GI) upset — Many dogs with an upset tummy consume grass because they instinctively know it will make them throw up. There seems to be something about the texture of grass that triggers vomiting or a bowel movement in many dogs, which relieves their discomfort. If this is the situation with your dog, he'll probably seem almost frantic to get outside to start gobbling up the nearest patch of grass.

The intensity of grass consumption for the purpose of vomiting is usually strong and the grass chosen appears to be less important. If the "cure" works, at some point he'll quit chewing, lick his lips (a sign of nausea in dogs), and throw up.

This is normal behavior for canines (who are, by design, scavenging carnivores and indiscriminate eaters) and nothing to be concerned about unless it happens more than once or twice a year. It's nature's way of helping dogs get rid of toxins from their bodies and bring their GI tracts back into balance.

Dogs who ingest grass to throw up are usually not selective about what grass they consume; they just want to induce vomiting and feel better. But there are several other reasons that dogs eat grass (and don't throw up). In fact, many dogs seek out specific grasses and are quite selective about what species they're looking for. There are several reasons dogs eat grass and don't throw up, including:

To balance the microbiome Grass contains prebiotic fiber that may help keep your dog's intestinal flora balanced and resilient.

To eliminate intestinal parasites — Chimpanzees consume plant material to increase intestinal motility to rid their bodies of intestinal parasites.1 It's possible dogs eat grass for a similar reason.

To fulfill specific nutrient requirements — In a 2008 study, researchers found that grass eating in domestic dogs is a normal tendency.2 This might be an inherited behavior, since wild canines eat entire prey animals, including the entrails (guts), which typically contain digested plant matter.

It's possible the grasses your dog likes to munch contain nutrients her body lacks. Grass is an abundant source of fiber. As a living green food, it contains phytonutrients, is high in potassium and chlorophyll, and is also a pretty good source of digestive enzymes. Your dog could be seeking out selective grasses to make up one or more nutrients she's not currently getting in her diet.

Does Your Dog Regularly Eat Grass?

If your dog's grass eating is chronic and especially if it causes her to vomit frequently, it's time to make an appointment with your veterinarian.

In the meantime, I recommend upgrading her diet if she's still eating kibble or any non-human grade commercial dog food. Most healthy dogs fed a nutritionally optimal, species-specific diet don't routinely consume an abundance of grass because they receive all the nourishment their bodies need from their food, and they rarely suffer from digestive issues. Adding probiotics and digestive enzymes can also benefit dogs with "sensitive stomachs."

If you're sure your dog is receiving optimal nutrition from her diet and her microbiome is healthy, but she still eats a significant amount of grass, consider growing your own sunflower sprouts. Sprouts can provide an easy, inexpensive source of fresh, live, organic vegetation and are much more nutritious than grass.

If your dog is selective about the grass she eats, choosing tall, broad grasses to nibble (the kind that typically grow along a fence line or between cracks in the sidewalk) and then moves on, she's most likely eating grass because she wants to or because she's seeking the nutritional or digestive benefits it provides. There's no cause for concern as long as you're sure the grass she's sampling is free of pesticides, herbicides, and other contaminants.