Why Dogs Eat Grass: A Complete, Science‑Led Guide to This Common Canine Behaviour Grass‑eating is one of the most frequently observed canine behaviours, yet it remains one of the most misunderstood. Guardians often wonder whether it signals a nutritional deficiency, digestive discomfort, boredom, instinct, or something more complex. This guide explores the physiology, behavioural science, gut health, and nutritional factors  behind grass‑eating in dogs—helping you understand