Why Do Dogs Eat Grass?
Dogs eat grass for various reasons: boredom, dietary fiber seeking, instinctive behavior inherited from ancestors, or because they simply like the taste and texture. Contrary to popular belief, most grass-eating dogs are not sick and don't vomit afterward. The behavior is common and usually harmless. However, ensure grass hasn't been treated with pesticides or fertilizers, and consult a vet if eating becomes excessive or obsessive.
Key Takeaways
- Studies show that fewer than 25% of dogs vomit after eating grass, debunking the common theory that dogs eat grass to induce vomiting when sick.
- Avoid letting dogs eat grass treated with pesticides, herbicides, or fertilizers - these chemicals are toxic.
- Some grass-like plants (like ornamental grasses or certain houseplants) can be toxic - know what's in your yard.
Explanation
Studies show that fewer than 25% of dogs vomit after eating grass, debunking the common theory that dogs eat grass to induce vomiting when sick. Most healthy dogs eat grass occasionally without any apparent digestive distress. It appears to be normal dog behavior with roots in their evolutionary history.
Several theories explain grass eating: ancestral wolves ate plant matter in prey stomachs; grass provides fiber that may aid digestion; some dogs enjoy the texture and taste, especially tender young grass; and bored dogs may graze to pass time. Some dogs may eat grass to fulfill an unmet nutritional need, though this is less common with balanced commercial diets.
While occasional grass eating is normal, sudden increases in the behavior, eating obsessively, or showing signs of illness warrant veterinary attention. Some dogs may have pica (eating non-food items) or gastrointestinal discomfort that drives excessive grass consumption.
A 2008 study in the journal Applied Animal Behaviour Science surveyed over 1,500 dog owners and found that 68% of dogs ate grass on a weekly basis and 79% ate plants of some kind regularly. Only 8% showed signs of illness before eating grass, and just 22% vomited afterward. Younger dogs were more likely to eat grass than older dogs, and dogs fed a raw meat diet ate grass less frequently than those on commercial kibble, suggesting a dietary fiber component.
The type of grass dogs prefer may not be random. Many dogs selectively choose young, tender blades of grass over mature, coarse ones. Young grass is higher in moisture content (85-90% water) and contains more digestible nutrients. Wild canids like wolves and coyotes regularly consume plant matter, with studies finding grass and berries in 11-47% of wolf scat samples. This suggests grass eating is a natural behavioral inheritance rather than a sign of domestication-related dietary deficiency.
Things to Know
- Avoid letting dogs eat grass treated with pesticides, herbicides, or fertilizers - these chemicals are toxic.
- Some grass-like plants (like ornamental grasses or certain houseplants) can be toxic - know what's in your yard.
- Puppies explore the world with their mouths and may eat grass out of curiosity.
- If your dog vomits frequently after eating grass, consult a vet - the vomiting, not the grass eating, is the concern.