Many dog owners have noticed their dogs munching on grass during walks or in the backyard, often sparking curiosity or concern.
It’s a common behavior among dogs, but you may worry whether this habit causes digestive problems or signals underlying health issues.
We outline why dogs eat grass, whether eating grass can upset their stomach, and what symptoms to watch for. We also explain when eating grass might be harmless and when it might indicate a need for veterinary care.
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Does Eating Grass Upset Stomach?
Generally, eating grass does not upset a dog’s stomach and is considered a normal behavior. Many dogs nibble on grass without any negative effects, and some even use it to help soothe mild stomach discomfort by inducing vomiting.
However, eating large amounts of grass or grass contaminated with pesticides, chemicals, or harmful plants can irritate the stomach lining and cause digestive upset such as nausea, vomiting, or diarrhea.
Also, if a dog frequently eats grass and shows persistent signs of stomach upset, it may indicate an underlying digestive issue that requires veterinary attention.
Therefore, while occasional grass eating usually doesn’t harm the stomach, excessive or problematic grass consumption can lead to or signal digestive upset.
Common Reasons Dogs Eat Grass
1. To Soothe an Upset Stomach
One of the most common theories is that dogs eat grass when they feel nauseous or have an upset stomach.
Grass can irritate their stomach lining just enough to trigger vomiting, helping them get rid of something unpleasant in their digestive tract.
If your dog is eating grass and then vomiting afterward, it may be a sign their stomach is upset.
In this case, eating grass can temporarily worsen stomach upset but also serve as a self-soothing mechanism.
2. Nutritional Deficiency
Sometimes dogs eat grass because they’re missing certain nutrients or fiber in their diet.
Grass contains fiber that can aid digestion, and some dogs instinctively seek it out to improve their gut health.
In such cases, eating grass does not necessarily upset the stomach. Instead, it may actually help with digestion and regularity.
Related: Dog eating grass after throwing up (Here’s why)
3. Boredom or Anxiety
Dogs may eat grass out of boredom or anxiety, especially if they don’t get enough mental or physical stimulation.
This behavior is similar to people chewing gum or fidgeting.
If your dog is eating grass due to boredom or anxiety, it is less likely to cause stomach upset unless excessive amounts are consumed.
4. Simply Enjoyment or Curiosity
Many dogs simply like the taste and texture of grass or are curious about their environment.
This natural exploration does not usually upset their stomach.
When Does Eating Grass Upset the Stomach?
While occasional grass eating is generally harmless, eating grass can upset a dog’s stomach in certain situations:
Overeating Grass
Eating large amounts of grass can irritate the stomach lining and digestive tract, causing discomfort, nausea, or vomiting.
This can lead to symptoms such as diarrhea, loss of appetite, and lethargy.
Related: Does eating grass help dogs’ stomach?
Consuming Contaminated Grass
Grass treated with pesticides, fertilizers, or herbicides can upset your dog’s stomach or even cause poisoning.
Ingesting contaminated grass may cause symptoms such as vomiting, diarrhea, excessive drooling, or weakness.
Eating Grass Due to Digestive Disorders
If your dog frequently eats grass and shows signs of an upset stomach, it might indicate an underlying gastrointestinal issue such as gastritis, inflammatory bowel disease, or intestinal parasites.
In these cases, eating grass may be an attempt to soothe chronic stomach discomfort, but it can also worsen the condition or mask symptoms.
Symptoms That Eating Grass Has Upset Your Dog’s Stomach
If eating grass is upsetting your dog’s stomach, you might notice the following signs:
Vomiting shortly after eating grass
Loose or watery stools (diarrhea)
Signs of nausea such as lip licking, drooling, or excessive swallowing
Loss of appetite or refusal to eat
Abdominal discomfort or bloating
Lethargy or weakness
Excessive thirst or dehydration
If your dog shows any of these symptoms after eating grass, it is a clear sign their stomach may be upset and veterinary attention might be necessary.
Related: Dog eating grass and leaves (Explained)
Should You Stop Your Dog From Eating Grass?
Since eating grass is normal behavior for many dogs, completely stopping it isn’t always necessary or even recommended.
However, there are important precautions to take:
Monitor the Behavior
Watch how often and how much grass your dog eats. Occasional grazing is normal, but excessive or compulsive eating can indicate a problem.
Check for Symptoms
Pay attention to signs of stomach upset such as vomiting, diarrhea, or changes in appetite and energy levels.
Avoid Toxic Plants and Chemicals
Ensure your yard and walk areas are free from pesticides, herbicides, or toxic plants that could harm your dog.
Provide a Balanced Diet
A well-balanced, nutritionally complete diet can reduce the need for dogs to seek out grass for fiber or nutrients.
Enrich Your Dog’s Environment
Reduce boredom and anxiety with plenty of exercise, play, and mental stimulation to prevent grass eating driven by stress.
When to See a Veterinarian About Grass Eating and Upset Stomach
It’s important to consult a vet if your dog’s grass eating is accompanied by:
Frequent or persistent vomiting
Bloody or severe diarrhea
Signs of dehydration (dry gums, sunken eyes)
Loss of appetite lasting more than 24 hours
Sudden behavior changes such as lethargy or aggression
Signs of poisoning or exposure to toxic plants or chemicals
Your vet can perform diagnostic tests to rule out underlying digestive issues or nutritional deficiencies and provide appropriate treatment.
Key Takeaway
Eating grass is common and usually not harmful to dogs.
Some dogs eat grass to relieve mild stomach upset or to supplement their fiber intake.
Eating grass can upset the stomach if consumed in large quantities, if the grass is contaminated, or if it signals an underlying digestive problem.
Watch for symptoms such as vomiting, diarrhea, or lethargy after grass eating.
Maintain a balanced diet, avoid toxins, and provide enrichment to prevent excessive grass eating.
Consult a veterinarian if your dog frequently eats grass with signs of stomach upset or illness.
By understanding why your dog eats grass and recognizing when it causes stomach upset, you can help keep your furry friend comfortable and healthy.