Why Do Dogs Eat Grass? The Real Reasons & What to Do

This content was reviewed and fact-checked by veterinarian Dr. Aukse Caraite, DVM.

Your dog has a full bowl of premium kibble—so why is he snacking on your lawn like it’s a salad bar? It’s one of the most perplexing behaviors dog owners face: a seemingly healthy pup munching on grass, sometimes casually, other times like it’s urgent. You might wonder if something’s wrong—are they sick? Bored? Nutrient-deficient? And should you stop them? Here’s the twist: most dogs eat grass at some point, and the majority don’t vomit afterward—debunking the popular belief that they do it to induce throwing up. So, if it’s not always about illness, what’s really driving this behavior? In this guide, we’ll break down the top scientific and behavioral reasons dogs eat grass, when it’s harmless vs. when it’s a red flag, and how to respond as a responsible owner.

Why Do Dogs Eat Grass?

Grass eating is a natural, routine behavior for most healthy dogs and is not typically a cause for concern. While many theories exist, according to the latest research, these are the main reasons dogs eat grass:

Other non-scientific reasons dogs eat grass:

1. Dogs’ wild ancestors (wolves, foxes) ate plant material found in the stomachs of their herbivorous prey.
2. They like the taste or texture.
3. Pica behavior (eating non-food items due to nutritional deficiency).
4. Grass-eating is a displacement behavior of boredom or anxiety.

How Common Is It for Dogs to Eat Grass?

Grass is the most frequently eaten plant by 79% of dogs. A comprehensive survey conducted by researchers at the University of California, Davis, revealed that approximately 68% of dogs engage in grass consumption on a daily or weekly basis. Furthermore, a broader study encompassing 1,571 dog owners found that 79% of healthy, well-cared-for dogs had eaten plants, particularly grass, at some point. This behavior is seen in both puppies and adult dogs, and is not linked to breed, sex, or diet type.[5]

Is Grass Eating Healthy For Dogs?

Yes and no. Nutritionally speaking, grass is not particularly beneficial for dogs—at least not in a meaningful or necessary way. However, grass has insoluble fiber, which can help with mild constipation or improve stool bulk.

Studies on Miscanthus grass, a type of grass, have shown it to be a promising alternative fiber source for dogs. It supports gut health and helps maintain healthy gut bacteria, much like traditional fiber sources such as cellulose. Compared to beet pulp, Miscanthus grass may lead to softer stools and improved nutrient absorption.[6],[7]

While doest can safely eat grass and benefit from its fiber content, grass doesn’t provide complete proteins, healthy fats, or key vitamins/minerals required in a dog’s diet. Grass shouldn’t be considered a dietary source of nutrients. Here’s a breakdown:

Dog Grass-Eating Behavioral Patterns

Dogs exhibit varying patterns in grass consumption:

Why Do Dogs Eat Grass Excessively?

The ASPCA notes that as long as the grass isn’t treated with harmful chemicals, and the behavior isn’t obsessive or accompanied by vomiting or other symptoms, there’s typically no need for intervention. However, when a dog eats grass excessively or in large amounts, it could be a sign that something deeper is going on. Excessive grass eating can sometimes be linked to medical issues such as gastrointestinal disorders, parasites, or other illnesses

Potential Risks to Be Aware Of

While occasional grass-eating is typically harmless, certain factors can pose risks:

• Chemical exposure: Grass treated with pesticides, herbicides, or fertilizers can be toxic to dogs.
• Parasites: Eating grass in public areas may expose dogs to intestinal parasites like roundworms or hookworms from contaminated feces.
• Digestive Issues: In rare cases, consuming large amounts of grass can lead to vomiting or even intestinal blockage

Sometimes dogs nibble on other plants growing alongside grass—some of which can be toxic. Common dangers include: foxtails, wild mushrooms, rulip bulbs or leaves. Always check your yard or walking areas for plant dangers.

Side Effects of Dogs Eating Grass

Only a small percentage of dogs (about 9%) appear ill before eating grass, and most do not vomit afterward (only 22% vomit frequently after eating plants).^[5]

The following symptoms may indicate a bad reaction to grass.

Dogs with grass-related skin issues often have immune reactions to specific proteins in grass leaves. Two proteins—beta-amylase and RuBisCO—may act as allergens, causing itching and skin lesions.^[8]

Are Dogs Allergic to Grass?

How to Stop Your Dog From Eating Grass

If your dog has developed a habit of eating grass excessively, it’s important to manage it—especially if the behavior becomes frequent, compulsive, or leads to vomiting or digestive issues. While occasional nibbling is usually harmless, consistent grazing can signal a deeper problem or develop into a risky habit.

Here are practical steps to help stop or reduce your dog’s grass-eating behavior:

✅ 1. Increasing fiber in your dog’s diet with high-fiber dog food or vegetables like pumpkin and carrots can reduce the urge to eat grass.

🎾 2. Providing more exercise through longer walks and active outdoor sport or play to help prevent boredom-related grass eating.

🧠 3. Boosting mental stimulation with interactive dog toys and training games keeps your dog’s mind engaged and less focused on grazing.

🐾 4. Teaching commands like “leave it” and rewarding your dog for obeying helps redirect their attention away from the grass.

🦴 5. Offering an indestructible dog toy or edible alternatives like leafy greens can satisfy your dog’s need to munch without turning to grass.

🩺 6. Regular vet checkups ensure there are no underlying medical issues like parasites or digestive discomfort causing the behavior.

🛑 7. Supervising your dog during outdoor time allows you to intervene and redirect before they start eating grass.

🚫 8. Avoiding lawns treated with chemicals protects your dog from toxic exposure when they do nibble on grass.

9. 🐕‍🦺 Using tools like a dog training collar with vibration or sound settings can help reinforce commands and discourage grass-eating behavior.

🐶 10. If the behavior continues despite your efforts, consulting a veterinarian or behaviorist can help identify and address deeper medical or behavioral causes.

What to Do If A Dog Reacts Badly to Grass

Dogs showing worsening symptoms, such as blood in their vomit or stool, difficulty breathing, weakness, or collapse, should be taken to the veterinarian immediately.

1. Contact a veterinarian immediately: Even if your dog seems fine, contact your veterinarian or an emergency pet poison hotline right away. This includes services such as the ASPCA Animal Poison Control Center at 1-888-426-4435 or the Pet Poison Helpline at 1-855-764-7661. If you can’t reach your vet, you can chat live with a registered online veterinary professional via our online vet chat or video chat support (24 hours a day, 7 days a week). You can also schedule an at-home veterinary appointment with The Vets, a mobile veterinary service that provides at-home vet care nationwide for just about everything.

2. Gather important information: When speaking to a veterinarian, provide the following details: the Quantity consumed (estimate if unsure), the time of ingestion, and the dog’s weight and breed (to assess potential risk).

3. Follow veterinary instructions: The vet may suggest monitoring at home or emergency treatment at the clinic.

• Bring any remaining grass to help the vet assess the situation.
• Keep your dog calm and prevent them from eating anything else.
• Be prepared to transport your dog to the vet quickly if advised.

The Bottom Line

Grass-eating is one of those quirky dog behaviors that’s usually harmless—but it can also be a subtle clue about your dog’s health, diet, or emotional state. In most cases, there’s no need to worry. But if the behavior becomes frequent, obsessive, or is paired with symptoms like vomiting or lethargy, it’s worth taking seriously. The key is to know your dog’s patterns, ensure their diet is well-balanced, keep them mentally and physically engaged, and consult your vet if anything feels off. With the right awareness and care, you can keep grass-eating in check—and your dog happy, healthy, and thriving.

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Sources

Canine Bible uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process and product review methodology to learn more about how we fact-check, test products, and keep our content accurate, reliable, and trustworthy.

1. Reduction in grass eating behaviours in the domestic dog, Canis familiaris, in response to a mild gastrointestinal disturbance
2. Grass-Eating Behaviour in the Domestic Dog, “Canis familiarise”
3. Grass eating patterns in the domestic dog, Canis familiaris
4. Human-directed gazing behavior in domestic dogs (canis familiarise)
5. Characterisation of plant eating in dogs
6. 112 Modulating Effects of Miscanthus Grass and Prebiotic Blends on Canine Fecal Microbiota, Metabolites, and Digestibility
7. The effects on nutrient utilization and stool quality of Beagle dogs fed diets with beet pulp, cellulose, and Miscanthus grass
8. Immunoglobulin E-specific allergens against leaf in serum of dogs with clinical features of grass leaf allergy.