Why Do Cats and Dogs Eat Grass?

Pets’ grass-eating habits in dogs and cats remain somewhat mysterious, with multiple theories but no single proven cause. Veterinarian Dr. Jamie Lovejoy notes that neither species can digest grass well, lacking specialized gut bacteria and anatomy. While a common belief is that grass soothes upset stomachs, studies show illness precedes grass-eating in only a small percentage of cases. Surveys reveal many pets eat plants regularly, with some vomiting afterward, but no link to hairball expulsion in cats.

Grass-eating has been observed in wild canines and felines, suggesting an instinctive behavior possibly tied to parasite control, though this is hard to confirm in modern pets. Nutritional needs are another theory, but balanced diets likely make this unnecessary.

Most grass-eating is harmless, but certain plants and chemically treated lawns can be dangerous. Persistent or compulsive eating, especially with frequent vomiting or abnormal stools, should prompt a Veterinary check. Often, pets simply eat grass because they enjoy it.