Why do dogs eat grass?

While no single definitive answer exists, veterinarians and animal behaviorists point to several common reasons why dogs eat grass. This behavior, known as pica, is generally considered normal for domestic dogs.

One popular theory is that grass eating is an ancestral trait. Wild canids, like wolves and foxes, often consume the entire prey animal, including the stomach contents of plant-eating animals. Eating grass may be an instinctual way for modern dogs to supplement their diet with fiber or nutrients they might be missing. Fiber aids in digestion, helping to pass food through the intestinal tract smoothly.

Another common belief is that dogs eat grass to induce vomiting when they feel unwell. Some dogs will frantically eat grass and then throw up shortly after, suggesting they use it to purge something that has upset their stomach. However, studies show that fewer than 25% of dogs vomit after eating grass, and most dogs don't appear sick beforehand. This indicates that self-medication isn't the primary driver for most grass-eaters.

For many perfectly healthy dogs, the reason may be much simpler: they just enjoy the taste and texture of it. It can be a source of enrichment or a way to alleviate boredom, similar to how humans might chew on a blade of grass.

Unless the behavior is excessive, accompanied by other signs of illness like lethargy or diarrhea, or if the grass is treated with pesticides, it's typically not a cause for concern.