Why Do Dogs Eat Grass

Why Do Dogs Eat Grass

July 24, 2015

by Dr. Mike Petty, DVM


Why do dogs eat grass? There probably isn’t one answer as there are probably many different reasons why dogs eat grass. A friend of mine asked me this question many years ago, and I replied, “Sometimes when I see a lush green lawn, I want to take a bite out of it as well.”   All kidding aside, some dogs might simply like the taste of it.

Dog behavior has been affected by our genetic manipulation from their wolf ancestors. This sometimes makes it hard to understand why they exhibit behaviors that are different from wolves. But it is known that wolves eat grass at about the same rate as dogs do. Why is this so?

One theory is that eating grass, an indigestible source of fiber for dogs, may help move intestinal parasites through the intestinal tract, hence lowering the number of worms living there. There would certainly be an evolutionary advantage to this, with an increase in health and subsequent increase in reproduction.

Another theory revolves around the idea that this might help them vomit. Certainly a lot of dogs that eat grass subsequently vomit. But this might be a chicken-or-the-egg conundrum; were they already feeling sick when they ate the grass or did the grass make them feel sick?

Perhaps the most important take-home message is that there does not appear to be any health concerns, as long as they are not eating grass that has been treated by a lawn service.