It’s like “which came first, the chicken or the egg”? Does a dog or cat vomit because it eats grass, or does it eat grass to vomit because it has an upset stomach? The frequently asked question is “Why does my dog or cat eat grass or plants“? For many years it was thought that there was a nutritional deficiency in the diet, or that they eat grass to induce vomiting because they are sick. Now a recent study of over 3000 pets revealed some interesting facts: 68% of the pet owners said their dogs eat grass or plants on a regular daily or weekly basis, only 8% reported that their dogs showed signs of illness before ingesting grass or plants, and 22% reported that their dogs regularly vomit after ingesting grass or plants. The study also found that younger dogs eat plants and grass more frequently than older dogs and the young ones were less likely to appear ill before, or vomit afterward. Cats, on the other hand, often eat grass or plants intentionally to induce vomiting because of hair balls. However, a few cats can eat grass and plants and do not show signs of illness before or vomit afterward. Regardless of the quality of the diet, eating these non nutritional members of the plant kingdom had little to no effect on the overall well being of the dog or cat. In the wild, cats, dogs, fox, wolves, etc. frequently eat grass and plants to vomit up worms. This definitely has a beneficial effect on their overall health, as worms are parasites and if the numbers get too high they can cause serious harm and even death. But, this is not the case in the well cared-for domesticated pets in civilized countries. The conclusion of the study was that this tendency of some dogs and cats to eat plants or grass is an inherited trait from their wild ancestors and is considered normal. Most importantly, keep your pets away from toxic plants and grass that has been treated with pesticides not listed as “pet friendly. If your dog or cat does not normally eat grass or plants and suddenly just started to do so, and is vomiting, your veterinarian should be consulted.