Yes one reason a dog eats grass is to induce vomiting. The grass goes to the stomach and binds with whatever it contains and then he vomits it. This is a behavior that protects a dog against food poisoning and indigestion. They seem to know which grasses and weeds to eat. Some of these weeds are the same that are found in the health food stores to boost emmune systems. Also, I learned that Rhus Tox, a homeopathic remedy for achy joints and rheumatism, is made from poison ivy, which dogs also eat, how smart can they be??? !!!