Why Do Dogs Eat Grass? 7 Reasons for This Habit

Dogs eat grass for a variety of reasons, and most of the time it’s normal behavior. But, you may still be wondering why do dogs eat grass?

dog eating grass
It’s normal for dogs to eat grass but grass can be harmful if it has pesticides fertilizers or other contaminants on it. © Aungsumol Chuachai/Getty Images
Last Updated on December 6, 2023 by Dogster Team

So, why do dogs eat grass anyway? Research on why dogs eat grass is limited, says Dr. Shadi Ireifej, board certified veterinary surgeon and chief of medicine at VetTriage. Many people think that grass is a primitive Pepto-Bismol that soothes heartburn and upset stomachs. Some believe the extra fiber in grass helps your dog go potty. And others believe eating grass is simply in your dog’s DNA.

The 7 Reasons Dogs Eat Grass

1. Settle a dog’s upset stomach

Dr. Sara Ochoa, a veterinarian at Whitehouse Veterinary Hospital, says tummy trouble is the main reason dogs eat grass. So, what’s in the grass-green vomit on your living room carpet? The icky parts of animals like hair, beaks, hooves and feathers, Dr. Ochoa says. Grass helps your dog throw up the less digestible parts of his meal.

Upchucking grass can instantly reduce your dog’s nausea, unlike other longer-lasting vomiting agents like 3% hydrogen peroxide. Switch your dog to a food brand that’s easier to digest, Dr. Ochoa says. A 2018 study published in the Journal of Animal Science found that mildly cooked and raw diets had higher nutrient digestibility than extruded diets.

2. Helps dogs with heartburn

When your pup has a troubled tummy, he can’t just pop an antacid, so he may gently nibble on grass. The green stuff contains pectin — a type of fiber that treats acid reflux. Dr. Ireifej says grass might calm your dog’s upset stomach because it has the same neutral pH as water. If your dog has an empty stomach, grass might mop up the excess bile and stomach acid. Should grass be your all-natural, go-to remedy for canine heartburn? Not so fast, says Dr. Ochoa. Lawn and turfgrass cannot relieve heartburn like over-the-counter medicines do for humans.

3. Constipation aid

An ounce of grass is 85% water and it has 4 grams of fiber. Grass can speed up digestion, Dr. Ireifej says, but, because your dog can’t digest grass, it winds through his gastrointestinal tract and pulls water with it. That increases the size of his poop, so it passes more quickly through his colon. Instead, offer dog-friendly fruits and veggies like bananas and broccoli. Work with a veterinarian because excessive fiber can cause gas and diarrhea. 

 4. Instinctive behavior

About 130,000 years ago, dogs came from gray wolves. While we think of our dog’s ancestors as meat-eaters, gray wolves are actually scavengers that eat whatever is available, including grass and berries.

Adult wolves might eat grass because it contains a green substance called chlorophyll, which could ease pain and reduce osteoarthritis symptoms in wild dogs, according to a 2022 study published in PLoS One. Wild wolf puppies (pups) may eat grass because they’re more prone to intestinal parasites. They’re still growing, so nutritional stress could make them easy targets for predators like bears and coyotes.

5. Nutritional deficiency

If your dog is gulping down grass, he might need more healthy fats in his diet, Dr. Ireifej says. When grass is cut, it forms omega-3 and omega-6 fatty acids. Dogs with low omega-3 levels are more likely to be aggressive, according to Veterinary Research Communications study. How many grams of omega-3 are there in a single blade of grass? It’s never been studied, so stick to fish and krill oil supplements.

6. Playful behavior

If your puppy treats your lawn like an all-you-can-eat salad bar, it might be because he is curious or bored, Dr. Ireifej says. Some puppies and adult dogs view the green stuff as a delicacy. They seek out the plumpest, juiciest blades of grass and slowly savor them. How do you keep your dog from eating grass? Teach the “leave it” cue. It will train your dog to automatically ignore grass. When he shows any interest in grazing, say “leave it” in a firm voice. Then when he comes to you, give him a high-value treat like a turkey hot dog and praise him.

7. Anxiety

When your pup hears birds chirping or a police car making a “woo-woo-woo-woo-woo” sound, he may start frantically eating grass, says Dr. Ochoa. Is your dog pacing and panting? Barking? Howling? These anxiety symptoms are usually caused by separation anxiety or stressful events like fireworks. Other hormonal conditions like Cushing’s disease and brain tumors can cause canine anxiety, too, Dr. Ireifej adds. Pica is a condition where dogs crave and compulsively eat non-food items like grass and rocks.

Veterinarians can determine whether your dog has generalized anxiety or another medical condition depending on his age, breed, gender, medical history and current medications.

Is It Safe for My Dog to Eat Grass?

Grass isn’t harmful or dangerous, but the products you spray on your grass can be harmful to your dog. Fertilizers may contain nitrogen, which can cause toxins to build up in your dog’s blood or shut down his kidneys.

Can you protect your dog from your pesticide-spraying neighbors? No, even if you don’t spray chemicals on your grass, they can drift from your neighbor’s treated yard. That’s why 50% of dogs from pesticide-free households still have weed and insect killers in their urine, according to the University of Maryland.

Eating feces-covered grass can inflame your dog’s stomach and intestines, and the eggs and larvae of worms may be lurking in the grass.

Is There a Type of Grass That’s Safe for My Dog to Eat?

Because dogs can’t digest the sugar in plants, every type of grass can cause vomiting or diarrhea. Is your dog excessively eating grass? Try indoor pet grass kits, such as Dog Grass Garden-In-A-Bag. They’re a blend of barley, rye, oat and wheat seeds. Dr. Ochoa says cereal grains can boost your dog’s immune system and have been shown to have anti-inflammatory properties. Before you jump on the DIY pet grass bandwagon, make sure your dog doesn’t have any grain allergies or other health concerns. Schedule an appointment with your veterinarian or a board-certified veterinary internist.

Is Grass Poisonous for Dogs?

The grass isn’t always greener on the other side. Don’t let your dog eat these dangerous grasses:

  • Grass palms: Believe it or not, palm trees are a type of grass. Grass palms are loaded with a bitter-tasting poison called saponin that can cause reduced appetite, dilated pupils, bloody diarrhea, depression and increased saliva. If you discover your dog has eaten grass palm, rush him to your vet.
  • Foxtails: Foxtails are grass-like weeds. Their barbed seeds can become lodged between your dog’s toes and inside his ears, eyes, nose, and tongue. If they aren’t removed in time, foxtails can result in yucky pockets of pus that need to be drained. They can also move from your dog’s nose to his brain or break through his skin and damage his stomach and spinal cord.

The Bottom Line

It is normal for dogs to eat grass. Grass alone isn’t harmful, but the pesticides, fertilizers and feces on lawn grass can hurt your pup. Check your garden and new areas for foxtails and grass palms, or grow your own dog grass. And talk to your vet if your dog excessively eats grass or starts munching on it out of the blue.

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