Myth: Dogs eat grass because they are deficient in a nutrient in their diet or to make themselves vomit.
Fact: Dogs on well-balanced rations and in remarkably good condition regularly eat grass, and many dogs can be observed to routinely eat grass and not vomit. Research has revealed most grass to be a relatively poor emetic, and other studies have documented several wild canid species who also commonly eat grass. So the idea that dogs eat grass because they are missing something in their diet does not stand up under scrutiny for a variety of reasons. Likewise, the notion that grass is used by dogs needing to vomit cannot be supported experimentally. Some dogs might just like the taste. Be careful, particularly in teething puppies—excessive ingestion of leaves, sticks, grass, and other plant material can lead to gastrointestinal obstruction.