Myth Check: Do Dogs Eat Grass Because They're Sick?

The self-medication story is mostly folklore. Here's what the evidence actually suggests.

The story everyone knows: a dog feels unwell, eats grass to make himself vomit, and feels better. It's tidy, it's intuitive — and the evidence doesn't really support it as the main explanation. 1

What observation actually shows

Grass eating is extremely common in perfectly healthy dogs, most dogs show no signs of illness before grazing, and only a minority vomit afterward. If it were primarily self-medication, you'd expect the opposite pattern. The mundane explanations fit better: dogs are opportunistic omnivores, grass is available, and some simply seem to like it. 1

When grazing is worth attention

The behavior itself is usually harmless. The context can matter: a sudden increase in frantic grass-gulping, grazing paired with drooling, lip-licking, or repeated vomiting, or a dog eating grass instead of meals — those combinations suggest nausea or digestive discomfort worth investigating. 2

Verdict: mostly myth. Casual grazing in a healthy dog is normal dog behavior, not a medical bulletin. Watch the context, not the habit. 1