If your dog has a habit of chewing grass, you’re not alone. Many dog owners are surprised—or even concerned—when they see their furry companion munching on the lawn like a goat.
So is it a sign of illness? Boredom? Or just something dogs like to do? The answer is not always straightforward, but this behavior is more common—and natural—than you might think.
We outline the reasons why dogs chew grass. We’ll also look at what you should do if your dog chews grass frequently or vomits afterward.
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Why Do Dogs Chew Grass? Here’s What It Really Means
Dogs chew grass for several reasons, including boredom, digestive relief, nutritional needs, or simply because they enjoy the taste and texture.
While it’s a common and usually harmless behavior, some dogs may eat grass to induce vomiting when they have an upset stomach.
Occasional grass-chewing is typically normal, but if it’s frequent or accompanied by symptoms like vomiting or diarrhea, it could signal an underlying health issue.
Common Reasons Why Dogs Chew Grass
1. Instinctual Behavior from Wild Ancestors
One of the most widely accepted explanations for why dogs chew grass is that it’s instinctual.
In the wild, canines consumed entire animals—including the stomach contents of herbivores.
This often included partially digested plant material.
Today’s domestic dogs may chew grass as a throwback to this ancestral dietary habit.
This ingrained behavior doesn’t necessarily indicate a problem.
If your dog chews grass occasionally without other symptoms, it could simply be instinct at play.
Related: Puppy eating grass and vomiting (Explained)
2. Dogs Chew Grass Due to Boredom or Anxiety
Another common reason dogs chew grass is boredom or stress.
Just like humans may snack or bite their nails when anxious, dogs sometimes chew grass as a form of self-soothing.
It gives them something to do, especially if they’re left alone or not getting enough mental and physical stimulation.
Grass chewing in dogs caused by stress might be accompanied by pacing, panting, whining, or licking surfaces.
If this sounds like your pup, increasing playtime, walks, and mental enrichment might reduce their grassy snack cravings.
3. Dietary Deficiencies: Is Your Dog Missing Something?
Some experts believe that dogs chew grass to compensate for a nutritional deficiency, such as a lack of fiber.
This theory suggests that chewing grass may help stimulate digestion or provide nutrients that are lacking in their current diet.
If your dog is eating a low-fiber or low-quality diet, this might lead to increased grass eating.
In these cases, switching to a high-quality, balanced dog food rich in fiber can help minimize the behavior.
While there’s no definitive proof that nutritional deficiency is the main cause of dog grass chewing, it’s worth considering if the habit appears suddenly or becomes frequent.
4. Digestive Upset
Another common belief is that dogs chew grass to make themselves vomit when they have an upset stomach.
While it’s true that some dogs vomit after eating grass, not all do—and not all dogs chew grass to vomit.
Some studies suggest that less than 25% of dogs vomit after grass chewing.
Therefore, vomiting after grass chewing may be more of a side effect than the primary reason dogs engage in it.
If your dog eats grass and throws up occasionally but seems fine afterward, it’s likely not a cause for concern.
However, if vomiting is frequent or persistent, it could point to a deeper gastrointestinal issue.
Related: Dog eating grass like crazy (Explained)
5. Dogs May Chew Grass Simply Because They Like It
Sometimes the answer to “Why do dogs chew grass?” is the simplest one: they enjoy it.
Dogs experience the world through their mouths, and grass may simply be appealing in taste or texture.
Especially if the grass is moist, fresh, or has an intriguing scent, your dog might just enjoy the chewing experience.
This type of dog grass chewing is harmless if the grass isn’t treated with pesticides or chemicals.
6. Parasites and Medical Issues
In rare cases, dogs chew grass due to intestinal parasites or other medical issues affecting the digestive system.
Intestinal worms or gastrointestinal discomfort might prompt your dog to chew grass excessively in an attempt to find relief.
If your dog’s grass-chewing behavior is new, constant, and paired with symptoms like weight loss, diarrhea, or lethargy, it’s essential to consult your vet.
A fecal test can check for parasites and help rule out other medical conditions.
7. Environmental Factors and Seasonal Triggers
Some dogs chew grass more during certain times of the year.
Spring and early summer often bring new plant growth, which can be extra tempting for dogs due to its softness, moisture, or smell.
If you’ve noticed your dog chewing grass only during specific seasons or after rain, it could be a result of environmental changes rather than an underlying issue.
Related: Dog eating grass and not eating (Explained)
When Is Grass Chewing in Dogs a Problem?
While occasional grass chewing is normal and usually harmless, there are times when it could signal a deeper issue. Here are some red flags to watch for:
Frequent vomiting after grass chewing
Diarrhea or soft stools
Loss of appetite
Lethargy or weakness
Sudden increase in grass consumption
Signs of abdominal pain or discomfort
If your dog chews grass excessively and shows any of the symptoms above, a veterinary consultation is necessary to rule out underlying problems.
Risks of Grass Chewing You Should Be Aware Of
While grass chewing in dogs isn’t inherently dangerous, it can pose risks depending on the environment.
Chemical Exposure: Lawns treated with pesticides, herbicides, or fertilizers can be toxic to dogs. If your dog ingests treated grass, it could lead to poisoning.
Parasites and Bacteria: Grass, especially in public areas, may be contaminated with feces from other animals, which can carry harmful parasites or bacteria.
Choking Hazard: In rare cases, long blades of grass can get stuck in your dog’s throat or irritate their gastrointestinal tract.
To minimize risk, ensure your dog only has access to untreated grass and keep an eye on public areas that might be contaminated.
What to Do If Your Dog Chews Grass
If you’re wondering what to do about your dog chewing grass, follow these steps:
Monitor the frequency: Is it occasional or constant? Is it paired with vomiting or other symptoms?
Evaluate their diet: Make sure your dog’s food is high-quality and fiber-rich. Consider speaking to your vet about nutritional needs.
Rule out medical issues: If grass chewing is new or excessive, consult a vet for a physical exam and possibly a fecal test.
Address boredom or anxiety: Offer more mental and physical stimulation. Puzzle toys, longer walks, or even basic obedience training can help.
Avoid chemical exposure: Don’t let your dog eat grass that’s been treated with lawn chemicals or is in high-risk public areas.
Key Takeaway
Dogs chew grass for a variety of reasons, including instinct, boredom, dietary needs, or digestive discomfort.
In most cases, it’s a normal behavior and not cause for alarm—especially if your dog is otherwise healthy.
However, if your dog frequently eats grass and vomits or shows signs of illness, it’s important to consult your vet to rule out underlying conditions.
By understanding why dogs chew grass and what to watch for, you can help your furry friend stay safe, healthy, and happy—whether they’re lounging in the yard or having their next grassy snack.