Why Do Dogs Eat Grass?

Short answer: most dogs eat grass simply because it's a normal canine behavior. They may do it from instinct, hunger, boredom, or because they like the taste, and usually nothing is wrong. Contrary to popular belief, most dogs aren't trying to make themselves throw up.

If you've ever watched your dog graze on the lawn like a tiny cow, you're not alone. Vets get asked about it constantly. Here's what the research actually says, when grass eating is harmless, and when it's worth a call to your veterinarian.

6 reasons dogs eat grass

Scientists still don't know exactly why dogs eat grass, and different dogs probably do it for different reasons. These are the leading explanations.

1. It's instinct

Dogs' wild relatives eat plants too. Research on wolves has found plant material in their stomach contents, and wolves, foxes, and coyotes have all been seen eating grass. Your dog's lawn snack may be an echo of that ancestry.

2. They're hungry

A 2007 study found dogs ate more grass before meals than after, and less later in the day. A dog with an empty stomach may simply be looking for something to chew.

3. They need more fiber

Grass is roughage, and some dogs may seek it out when their diet is low in fiber. In one published case, a Miniature Poodle that had eaten plants and vomited for seven years stopped completely after switching to a high-fiber diet.

4. They like the taste

Some dogs seem to enjoy grass, especially fresh, wet spring shoots genuinely. Puppies also explore the world with their mouths, and grass is an easy thing to try.

5. They're bored or anxious

A dog left alone in the yard with nothing to do may graze to pass the time. Some anxious dogs chew grass for comfort, much like a nervous person bites their nails.

6. It gets your attention

If you rush over every time your dog eats grass, they may learn it's a great way to get you to notice them. Pulling them away can even make grass seem more tempting.

What about upset stomachs?

Many owners believe dogs eat grass to make themselves vomit. The evidence doesn't support that for most dogs. In a UC Davis study, only about 22% of dogs regularly vomited after eating grass, and just 9% showed signs of illness beforehand. The researchers concluded grass eating is normal dog behavior.

Some dogs do frantically gulp grass on an empty stomach and bring up yellow bile. In those cases, vets often suggest a small meal first thing in the morning or right before bed.

Is it safe for dogs to eat grass?

Grass itself is mostly harmless, and it passes through a dog's gut largely undigested. The real risks come from what's on or near the grass:

• Pesticides and herbicides. Treated lawns can poison dogs. Signs include drooling, nausea, vomiting, diarrhea, and loss of appetite.
• Parasites and germs. Grass contaminated with other animals' droppings can carry roundworms, hookworms, and viruses such as parvovirus.
• Toxic plants. Many garden and house plants are poisonous to dogs, so watch what else they nibble.
• Too much grass. Large amounts, especially mixed with other non-food items, can cause an intestinal blockage.

When to call the vet

Occasional grazing in a dog that otherwise acts normal is nothing to worry about. Call your veterinarian if you notice any of these:

• Your dog suddenly eats grass much more often, or frantically and in large amounts
• Frequent vomiting after eating grass
• Diarrhea, bloody stool, weight loss or a drop in appetite
• Lethargy or repeated lip licking, which can signal nausea
• Eating other non-food items like rocks, dirt or fabric, which may point to a condition called pica
• Eating grass that was recently treated with chemicals (bring the product label with you)

How to stop your dog from eating grass

If the habit is excessive, or your dog grazes on lawns you can't vouch for, these steps can help:

1. Feed a complete, balanced diet. Choose a food that meets AAFCO standards for your dog's life stage, and ask your vet whether more fiber would help.
2. Try smaller, more frequent meals. A bite of breakfast first thing in the morning can stop empty-stomach grazing.
3. Walk after meals. A full dog is less likely to snack on the lawn.
4. Teach "leave it." Calmly redirect your dog to a treat or toy instead of scolding them.
5. Beat boredom. Join your dog in the yard, play fetch, and offer safe chew toys.
6. Keep them leashed in grassy areas that may have been sprayed or fouled.
7. Grow a pet-safe patch. If your dog loves greens, give them untreated grass you've grown yourself.
8. Keep fresh water outside, since some dogs chew wet grass when they're thirsty.

The bottom line

Eating grass is one of the most normal things a dog can do. Keep them off chemically treated lawns, stay current on parasite prevention, and watch for changes. If your dog suddenly starts grazing more, or seems sick before or after, check in with your vet.

Sources

• Why Do Dogs Eat Grass?, PetMD, by Wailani Sung, DVM, updated March 2026
• Why Does My Dog Eat Grass?, American Kennel Club, updated April 2026
• Why Do Dogs Eat Grass?, VCA Animal Hospitals
• Characterisation of plant eating in dogs, UC Davis School of Veterinary Medicine

This article is for general information and isn't a substitute for advice from your veterinarian.