Why does my dog eat grass? Causes and when to worry

A habit more common than you think

If your dog eats grass, it's in good company. Owner surveys suggest the vast majority of dogs do it at some point, and many do it often. Vets consider it normal behavior in healthy dogs, although there's still no single explanation for it.

The "it feels sick" myth

Many people believe dogs eat grass to make themselves vomit when their stomach hurts. Studies suggest otherwise: most dogs don't seem ill before eating it, and only a minority vomit afterwards. In other words, eating grass is rarely a way to "self-medicate". It seems more like something many dogs simply enjoy.

The most likely causes

• Ancestral behavior: wolves and wild dogs eat plant material, sometimes from their prey's stomach and sometimes directly. It may be an instinct that has stuck around.
• They like it: tender spring grass has a texture and taste many dogs seek out.
• Boredom: a dog with little exercise or stimulation may look for something to do.
• Fiber: some experts think certain dogs seek extra fiber, though this isn't proven for every case.
• Anxiety: for some dogs, chewing grass may be a way to calm down, like chewing objects.

Is eating grass dangerous?

Grass itself isn't usually harmful, but there are risks around it:

• Pesticides and fertilizers: lawns and parks treated with chemicals can poison your dog. Don't let it graze in unfamiliar or freshly sprayed areas.
• Toxic plants: dangerous plants can grow among the grass. Check the plants around your home with our Is it toxic? tool.
• Parasites: grass can carry parasite eggs from other animals' feces. Keep deworming up to date.
• Foxtails and grass awns: some dry grasses have sharp seeds that lodge in the mouth, nose, ears or between toes.

When to see your vet

Make an appointment if your dog eats grass frantically or suddenly much more than before, vomits often, has diarrhea, loses appetite or weight, seems lethargic or you notice blood in vomit or stool. Also if it tries to vomit without bringing anything up and its belly looks swollen: in large dogs this can be bloat, which is an emergency.

How to reduce the habit if it worries you

• Increase exercise and sniffing games: a tired, entertained dog looks for fewer distractions. Work out its needs with the walk planner.
• Bring treats on walks and teach "leave it" to redirect its attention.
• Offer chew toys at home.
• If your vet recommends it, review its diet in case it needs more fiber.
• If you'd like it to have something green safely, grow chemical-free wheatgrass or oat grass in a pot.

What if it eats things that aren't food?

Eating grass is different from eating dirt, rocks, socks or plastic. That behavior, called pica, can come from boredom, anxiety, hunger or sometimes health problems or deficiencies. Swallowed objects can also cause intestinal blockages that need surgery. If your dog eats non-food items, keep them out of reach and talk to your vet.

Read its body language

Noticing when it eats grass gives you clues. Does it happen when it's bored, nervous or always in the same spot? Is it relaxed or rushed? Learn to read its postures with our What is my pet telling me? tool. Writing these moments down in its journal gives your vet useful information if the behavior ever changes.

Frequently asked questions

Should I stop my dog from eating grass? Not necessarily. If it's healthy and the grass is chemical-free, small amounts usually aren't a problem.

Why does it vomit after eating grass? Long blades can irritate the stomach. If it vomits often, see your vet.

Do cats eat grass too? Yes. Many cats do, and it helps them bring up hairballs. Offer them cat grass.

This article is for information only and does not replace a visit to your vet.