Common knowledge says that dogs eat grass if they have an upset stomach so they will vomit. This is true to a certain extent but not the only reason dogs eat grass. Your dog may also eat grass because he is bored or may even just like the taste of grass. And dogs are omnivores so grass may help manage a dietary insufficiency. Check that the grass your dog eats has not been treated with fertilizers or pesticides since they can make your dog sick or even kill him.  Use only pet-safe chemicals on your lawn. Don’t leave your dog alone in the yard for long periods of time since he may start munching away. And if your dog occasionally vomits grass, it is probably manageable. However, if your dog vomits frequently, make an appointment with your North Phoenix, AZ veterinary clinic for evaluation and possible treatment.