Why Does My Dog Eat Grass?

Usually because they like it, and it is normal. Grass eating is one of the most over interpreted behaviors in dog ownership. The common belief is that a dog eats grass to make itself vomit, or because something is missing from the diet. The available research does not support either as the usual explanation. In the largest survey of the question, the great majority of owners reported their dogs ate plants regularly, most of those dogs showed no signs of illness beforehand, and only a small minority vomited afterward. In other words, for most dogs, most of the time, it is a normal thing dogs do.

That does not mean you should never pay attention to it. There is one pattern that is worth a vet call, and I will get to it.

What the evidence actually says

Studies looking at plant eating in domestic dogs have consistently found the same shape of result. Something like three quarters of dogs eat plants with some regularity. Of those, only around ten percent showed signs of feeling unwell before eating, and only around a quarter vomited afterward. Younger dogs eat plants more often than older dogs and are less likely to vomit afterward, which is the opposite of what you would expect if the behavior were a self medication strategy.

Nobody has demonstrated a link between grass eating and diet quality or fiber content either. Dogs on raw diets, kibble, and home cooked food all do it at similar rates.

The most likely explanations are unremarkable.

• It tastes good. New spring growth is sweet. Dogs eat it seasonally in a way that tracks the grass rather than the dog.
• It is something to do. Bored dogs graze. So do dogs in a novel environment.
• It is an inherited foraging behavior. Wolves and free ranging dogs eat plant material regularly, and it may help move intestinal parasites through the gut. Useful across a population even if it does nothing for your individual, well dewormed dog.
• It gets a reaction. If every grazing session produces a shout and a leash pop, some dogs will do it more, not less.

The pattern that is worth a vet visit

Here is the distinction that matters, and it is about the manner rather than the fact of eating.

Casual grazing looks like a dog selecting particular blades, chewing them, and carrying on with the walk. That is fine. What is not fine is frantic, indiscriminate eating: a dog gulping mouthfuls of whatever is underfoot, often paired with lip licking, repeated swallowing, drooling, a hunched posture, restlessness, or trying to eat dirt and mulch as well.

That frantic pattern is genuinely associated with gastrointestinal discomfort and it is worth a call. So is any of the following.

• A sudden onset in a dog who never did it. Behavior changes that appear in a week are worth investigating.
• Grass eating with vomiting more than about once a week.
• Any weight loss, appetite change, or change in stool alongside it.
• Eating grass and then straining, or being unable to bring anything up.

If the behavior is longstanding, casual, and the dog is otherwise thriving, it is a habit, not a symptom.

The real risks, which are not about the grass

The grass itself is close to harmless. What is on it is not.

• Lawn chemicals. Herbicides and fertilizers are the actual hazard, especially on other people's lawns and on the strips beside sports fields. If you treat your own lawn, keep the dog off it for the interval on the label, which is usually 24 to 48 hours.
• Foxtails and grass awns, in the western and southwestern United States. These barbed seed heads migrate into gums, throats, and paws and cause abscesses. Late spring through summer is the risk window.
• Slug and snail bait, which is often placed at the base of plants in exactly the areas dogs graze.
• Parasite eggs in areas with heavy dog traffic. Keep the deworming schedule current if your dog is a regular grazer.

If you want to reduce it anyway

Some people simply do not want it happening, usually because of the vomiting on the rug afterward. Fair enough. Do not punish it, because you will just teach the dog to eat faster when you are not looking, which is worse. Manage it instead.

• Feed before the walk, not after. A dog with something in the stomach grazes less.
• Teach and pay a leave it on the walk itself, not in the kitchen. Ten reps a walk, paid with something better than grass.
• Change the route for two weeks. A lot of grazing is location specific habit rather than a general urge.
• Add sniffing time on purpose. Five minutes of nose work in long grass often replaces the eating entirely, because a lot of grazing is a bored dog looking for input.
• Increase the pace. Grazing needs a stationary dog. A walk with more forward motion and fewer stops produces less of it.

The bottom line

If your dog is bright, eating normally, keeping weight on, and casually chewing a bit of grass on walks, you do not have a problem to solve. It is not a nutritional deficiency, it is not a sign of a bad diet, and it is not usually a stomach ache. Watch how it is eaten rather than whether it is eaten, keep an eye on what has been sprayed where you walk, and otherwise let it go.

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Every drill in this article comes from the WorldWide K9 Academy course library. If you want the full step by step system, start with the $5 intro course.