Sometimes dogs eat grass. It's a common behavior, but to us it may seem strange or unnerving. Dogs may eat grass in their yard, at the park or along the street for many reasons. A dog's desire to munch on the lawn may stem from many sources, such as indigestion, a need for nutrients or simply boredom. The primary concern with letting your dog eat grass is that it might have been treated with pesticides or herbicides.
The Need for Fiber
If your dog nibbles grass regularly, this may be a sign he's lacking something in his diet. Some dogs will instinctually chew on grass because they need more roughage. Lack of fiber can be the result of eating low-quality dog food or a diet too high in animal protein.
Dogs who are underfed will seek out nourishment anywhere they can. In addition to stealing snacks from the garbage, unattended plates or any low-lying food, they may also eat anything they find outside that seems reasonably tasty, like grass. If your dog is highly active make sure he's receiving enough nutrients, including from plants.
Animals who are bored do some odd things to keep busy. Dogs use their mouths to keep themselves occupied much as people do with their hands. A dog who is bored may chew on what's handy, including grass. More interactive play with you or other dogs may prevent your dog's desire to chew grass while he's outside.
Dogs are omnivores, meaning they need to eat foods other than meat to meet all their nutritional requirements. Wild dogs eat grass and plants in their environment as part of their regular diet. Even if your dog is eating good quality dog food with a balance of protein, fiber, carbohydrates and fat, he may still feel the instinctual desire to gnaw on some greens.
Because dogs cannot digest large amounts of fibrous plant material at a time, eating big tufts of grass rapidly can cause a dog to vomit. Dogs with an upset stomach may chew on grass to make themselves throw up. If your dog chows down on large amounts of grass, only to regurgitate it undigested a few minutes later, this could mean he felt the need to purge and used grass as his means to do so. If this is a frequent behavior for your dog, consult with your veterinarian about a possible cause for those tummy troubles.