Why Do Dogs Eat Grass?  

November 21, 2023
Diana Bocco
Reviewed By: 
5 minute read

"Is my dog turning into a cow?" This question has probably crossed your mind once or twice when you see your pooch happily grazing on your lawn. We get it, dogs’ passion for grass-eating is a bit of a head-scratcher. After all, why do our canine pals, known for their meat-loving tendencies, suddenly decide to snack on greenery?

Turns out that grass-eating is actually very common. A survey conducted by the University of California, Davis, found that out of 1,000 dog owners, 79% claimed their dogs ate grass at some point.1 This makes the behavior quite common and “normal” rather than suggesting nutritional or behavioral problems. 

So why does a dog eat grass? Let’s take a closer look into the world of canine science to figure out why our dogs have become the cutest 'lawnmowers' we've ever encountered.

Tracing the Roots: The Evolutionary Story Behind Dogs Eating Grass

Would you be surprised to hear that when dogs eat grass, it's often due to their wild ancestors? Well, that’s exactly how it is — while dogs are primarily known for their carnivorous diet, their ancestors had a more varied diet. 

Studies looking into canine ancestry have found that ancient dogs were a mix of hunters, scavengers, and foragers before humans came into the picture.2 The behavior, still observed in wolves today, is not just about filling a gap in their diet but also about seeking medicinal benefits. For example, wild canids are known to consume certain plants and grasses to aid in digestion or expel intestinal parasites.3 While your dog likely doesn’t need to eat grass anymore to get rid of parasites if he’s regularly dewormed, they might have retained this trait from their wolf ancestors.  

So while the sight of a dog eating grass can be puzzling, it's often just a normal part of canine behavior — a reminder of their rich and wild heritage.  

Other Reasons Behind Dogs Eating Grass

While evolutionary habits play a significant role in why dogs eat grass, there are also other reasons such as health issues, nutritional needs, or psychological factors. More importantly, the reasons why dogs eat grass may vary from dog to dog, ranging from boredom to dietary deficiencies.  

For example, you might have noticed that when dogs eat grass, they sometimes do it to induce vomiting if they're feeling unwell — especially if they have eaten something that doesn’t agree with their stomach.4 However, this reason may not be as common as you think. In fact, experts point out that less than 25% of dogs that eat grass actually vomit afterward and only 10% “seem to be sick before eating grass” — which suggests that nausea might not be the primary reason why dogs eat grass.5

If you notice your dog eating grass frequently, it might also be a good idea to check their diet for any nutritional deficiencies. Studies suggest that some dogs might be eating grass to supplement their diet, particularly to fulfill a need for fiber.6 Fiber is essential for digestive health, and grass is an easy-to-access source. While commercial dog foods are designed to provide balanced nutrition, some contain a low amount of fiber, which might lead to your pooch hunting for some extra in your yard. 

Finally, boredom or anxiety can also lead your dog to nibble on grass — especially in dogs that are left alone for extended periods, lack sufficient mental and physical stimulation, or experience anxiety. For many dogs, the act of eating grass can become a distraction or even a self-soothing behavior.  

The Effects of Grass Eating on Canine Health 

So is it okay for dogs to eat grass? The short answer, according to experts, is that grass, in its natural state, is not harmful to dogs. However, lawns that have been treated with chemicals like pesticides or fertilizers can pose a significant risk to dogs. Many of these substances can be toxic if ingested, causing everything from mild gastrointestinal upset to more severe poisoning symptoms. 

While untreated grass is generally safe, it could potentially cause stomach irritation, gastrointestinal upset or blockage if consumed in large amounts or too quickly. Plus, there’s always the risk your dog might ingest intestinal parasites that can be present in soil or on grass. 

Finally, it's important to keep in mind that eating grass could be a sign of an underlying health issue, such as gastrointestinal distress or a nutritional imbalance, which might require attention from a veterinarian. Veterinarians will examine behavioral patterns to understand why dogs eat grass, considering both psychological and physical health aspects. 

Managing Your Dog’s Grass-Eating Habit

Observing your dog munching on grass can be a peculiar sight, but as pet owners, it’s crucial to know how to manage and respond to this behavior. This includes recognizing when to be concerned, making dietary adjustments if necessary, and providing environmental enrichment to prevent boredom-induced grass eating.  

If the grass-eating behavior is something new (and it appeared suddenly), a veterinary check-up can help rule out or diagnose any medical concerns. Additionally, if your dog shows signs of illness such as vomiting, diarrhea, or lethargy, along with increased grass eating, you should contact your vet right away.

Other changes you can make: 

  • Dietary Adjustments. If you suspect your dog is eating grass due to a lack of certain nutrients, a diet change or supplement might be a good idea. Any big diet changes should be made under the guidance of a veterinarian or a canine nutritionist to ensure it's appropriate and safe for your pet.
  • Environmental Enrichment. The AKC recommends increasing exercise and interactive playtime to keep your dog mentally and physically engaged. Activities like long walks, fetch, agility training, or puzzle toys can significantly enrich your dog's environment and help fight boredom and anxiety. These activities might prevent grass eating but also contribute to your dog's overall health and happiness. 


While grass-eating is generally harmless, staying vigilant about your dog’s overall behavior and health is key. Remember, when in doubt, a vet’s insight can help keep your grass-munching buddy healthy and happy! 

At Cola's Kitchen, we provide nutritionally balanced, high-quality food that caters to the specific needs of dogs. Our recipes are crafted to provide a well-balanced diet that minimizes the need for dogs to seek out supplementary nutrients from sources like grass.  

about cola's precision diet

Cola's Kitchen precision diet is the first truly tailored diet for a unique approach to nutrition. Our diets are individually formulated and balanced to address the most precise nutritional requirements of your pup.

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