Why do dogs eat grass?

The self-medication story, dogs eat grass to make themselves throw up, mostly fails inspection. In the largest survey research, from UC Davis, only about 8 percent of grass-eating dogs showed signs of illness beforehand and fewer than a quarter vomited afterward. Grass eating is instead extremely common, most dogs do it, and wild canids do too, plant matter shows up regularly in wolf scat.

The mundane explanations lead: dogs appear to simply like grass, especially fresh spring growth, and grazing may reflect normal scavenger ancestry, mild boredom, or a bid for attention that reliably works. A fiber angle is plausible in some dogs; one case report described grass eating stopping after a diet change.

When to actually care: sudden frantic grazing paired with gulping and repeated vomiting, or any grass treated with lawn chemicals, since pesticides and fertilizers are the genuine hazard in this story. Otherwise, let the dog have the salad.