Every dog owner’s seen his pet rush to the door only to chow down on the nearest patch of grass. While common knowledge holds that this is a quick fix for Fido to make himself sick, vets have largely debunked this myth. Dogs lack the enzymes needed to digest grass, too, meaning there is little nutritional value in their grazing. So the question remains: Why do dogs engage in this seemingly senseless behavior?
 
Unlike their feline counterparts, dogs are not full-fledged carnivores. For thousands of years, canines operated as opportunist omnivores, scavenging most anything that met their dietary needs. Modern dogs, however, no longer eat like their predecessors. While wild dogs often ate their prey in its entirety, including the stomach contents of plant-eating animals, our pets consume a very different diet. This may explain why some seek out grass as an alternative food source. Some theorize that grass helps improve digestion, especially in cases where Fido is lacking in fiber.
 
While eating plant matter may come naturally to dogs, this doesn’t explain why your canine companion sometimes throws up after eating grass. Some theorize that dogs intentionally graze on grass to make themselves sick when they’re not feeling well— to ease nausea or bloating, to clear a blocked digestive tract, or as a reaction to parasites or bacteria, for example. Evidence suggests the vast majority of foraging canines aren’t ill when they start eating grass, however, and veterinarians have found that less than a quarter of dogs that eat grass regularly throw up afterwards.
 
While some dogs seek out grass and other vegetables matter due to nutritional deficiencies or an upset stomach, vets believe many cases of “pica” — eating things that aren’t food, including grass — are simply a sign of boredom. If you suspect your dog’s pica is due to under-stimulation, ensure he’s getting enough exercise by engaging him in fun activities such as playing interactive games together or buying him a chew toy. If, on the other hand, you suspect your dog’s grazing is due to a nutritional deficiency, try switching to a higher quality dog food with more fiber. Some dogs, however, may continue eating grass simply because they like eat. Though experts agree that grazing isn’t harmful in and of itself, pesticides used on lawns can be toxic when ingested by your canine companion. And while some afternoon snacking on grass is normal, you should take your dog to the vet if he seems distressed or eats grass often in order to vomit, as these may be signs of underlying veterinary conditions.