Why Do Dogs Eat Grass?

If you’re a dog owner, you’ve likely witnessed your pup munching on grass at some point.

This behaviour can be puzzling, especially when followed by a sudden bout of vomiting.

But why exactly do dogs eat grass, and is it something to be concerned about?

Dogs eat grass for several reasons, including digestive relief, nutritional supplementation, and instinctual behaviour.

Eating grass may help with nausea or provide fiber.

Some dogs also eat grass out of boredom or to fulfil natural grazing tendencies.

Here, we dive into the most common explanations supported by both observation and research to help answer this age-old question.

Common Explanations For Grass Eating In Dogs

While there’s no single, definitive answer, researchers have identified several theories that could explain why dogs exhibit this behaviour.

Here are some of the main explanations:

1. Digestive Aid

Some dogs may eat grass as a natural way to relieve stomach discomfort.

Grass can act as a mild irritant to the stomach lining, which may trigger vomiting and potentially help the dog feel better if it has ingested something unpleasant.

However, research shows that dogs don’t always vomit after eating grass.

In a 2008 study conducted by veterinarians Karen L. Sueda, Kelly M. Hart, and Benjamin L. Hart at the University of California Davis, only 9% of surveyed dogs appeared ill before eating grass, and just 22% vomited afterward.

This suggests that while some dogs might eat grass to induce vomiting, for most dogs, it’s not the primary reason.

2. Nutritional Needs

Dogs are primarily carnivores, but they also display omnivorous tendencies and might seek out greens to fill dietary gaps.

Grass contains fiber and trace nutrients, so dogs might eat it to supplement their diet, especially if their current food lacks enough fiber.

Although there’s no strong evidence linking grass-eating directly to dietary deficiencies, some researchers hypothesise that dogs with low fiber in their diet (like raw meat diets) may consume more plant material to balance their intake.

While it’s an intriguing idea, more controlled studies are needed to confirm this connection.

3. Behavioural Reasons (Boredom Or Curiosity)

Sometimes, grass-eating might simply be a product of curiosity, boredom, or the need for sensory stimulation.

This behaviour is especially common in puppies and younger dogs, who are naturally more curious about their environment and often explore it with their mouths.

A study in 2010 observed that dogs were more likely to eat grass during moments of relaxation or idleness, suggesting that it could serve as a form of entertainment or even attention-seeking behaviour.

Dogs that don’t get enough exercise or mental stimulation might also be more prone to eat grass as a way to pass the time.

4. Ancestral Behaviour

Grass-eating may be instinctual, stemming from the dietary habits of dogs’ wild ancestors.

Wild canines, such as wolves, sometimes eat grass and other vegetation as part of their natural diet.

This behaviour may help them ingest residual prey material or promote a healthy digestive tract.

Research published in the Journal of Veterinary Behaviour indicates that wild canines incorporate plant material into their diets, suggesting that modern dogs may have inherited a similar instinct.

While domestic dogs have a more refined diet, it’s possible they may retain this ancient inclination to eat greenery.

5. Taste Or Texture

It’s also possible that dogs simply enjoy the taste or texture of grass.

The cool, moist texture and fresh scent might appeal to them, especially on soft, tender blades of grass.

Dogs, like people, have individual preferences, and some may just have a liking for the unique taste and texture of grass.

This might explain why some dogs return to grass-eating frequently, even when other explanations don’t seem to apply.

Health Considerations For Grass-Eating

While grass-eating is generally harmless, there are a few precautions to keep in mind.

Lawns treated with pesticides, herbicides, or other chemicals can be toxic if ingested.

It’s always best to keep dogs away from treated grass areas.

Additionally, if your dog eats grass frequently and vomits afterward, or shows other signs of illness, it might be worth consulting your veterinarian to rule out underlying health issues.

Should You Be Concerned About Grass-Eating?

In most cases, occasional grass-eating is not a cause for concern.

It’s typically harmless and can be attributed to a combination of instinct, mild dietary curiosity, or a simple preference for the taste and texture of grass.

However, if your dog’s grass-eating becomes excessive or is accompanied by other symptoms like lethargy, weight loss, or frequent vomiting, it’s wise to consult your vet to ensure there’s no underlying health condition.

Here’s a breakdown of potential diagnostic tests a vet might perform to determine if there’s an underlying condition contributing to the behaviour:

1. Complete Physical Examination

Purpose: To evaluate the dog’s overall health and detect any visible signs of illness, pain, or discomfort.

Process: The vet will examine the dog’s mouth, throat, abdomen, and general condition to check for signs of nausea, pain, or gastrointestinal issues.

The physical exam helps to determine if further tests are necessary.

2. Faecal Analysis

Purpose: To identify internal parasites, such as worms or giardia, which can cause gastrointestinal upset, poor nutrient absorption, and increased interest in grazing behaviours.

Process: The vet will analyse a stool sample for parasites, bacteria, or abnormal cells.

This is a standard test in dogs with gastrointestinal symptoms.

3. Blood Tests (Complete Blood Count and Biochemistry Profile)

Purpose: To assess the dog’s overall health, detect infections, and identify any metabolic or organ-related issues that could be causing nausea or discomfort.

Process: A Complete Blood Count (CBC) checks for signs of infection, inflammation, or anaemia, while a biochemistry profile assesses liver, kidney, and pancreatic functions, and checks glucose and electrolyte levels.

4. Urinalysis

Purpose: To detect urinary tract infections, dehydration, and metabolic or systemic issues that could influence appetite or cause gastrointestinal signs.

Process: Urine is collected either by free catch or via cystocentesis (placing a needle in the bladder).

The collected urine is then looked at for specific gravity, pH and protein levels, and spun down to be looked at on a slide under a microscope for cells that indicate infection, crystal types, and any irregularities in kidney function, which can sometimes correlate with digestive signs.

5. Abdominal X-rays, Ultrasound, Fluroscopy

Purpose: To visualise the stomach, intestines, and other organs to identify blockages, tumours or structural abnormalities that may be causing nausea or discomfort.

Process: Your pet will likely require mild sedation and/or anaesthesia to facilitate taking an xray and/or performing an ultrasound. Fluoroscopy is usually performed without sedation.

Ultrasounds provide more detailed imaging of soft tissue compared to X-rays.

Fluoroscopy allows us to visualise movement of food in real-time.

6. Endoscopy

Purpose: To visually examine the oesophagus, stomach, and upper intestines for abnormalities or blockages.

Process: Your pet will be anaesthetised while an endoscope (a flexible tube with a camera) is inserted via the mouth into the stomach to look for any ulcers, tumours, or other gastrointestinal problems that might cause nausea or drive grass-eating behaviours.

7. Allergy Testing or Dietary Trial

Purpose: To determine if food allergies or intolerances are causing digestive upset that leads to grass-eating.

Process: The vet will recommend either a special hypoallergenic diet and or specific homemade diet trial for a minimum of 8 weeks to see if symptoms improve with dietary change.

You will not be able to feed any other type of food, including treats and some supplements.

With these tests, a veterinarian can work through the possible causes and, if necessary, develop a treatment plan to help manage the behaviour and any associated health issues.

When to Consult a Veterinarian

It is best to contact a vet when grass-eating is accompanied by:

• Frequent vomiting
• Lethargy or loss of interest in activities
• Weight loss
• Changes in stool or persistent diarrhoea

While occasional grass-eating is normal, persistent symptoms could signal an underlying health issue that needs attention.

Key Takeaways

Grass-eating is normal: Most dogs will eat grass from time to time, and it’s usually harmless.

Behavioural and dietary factors may contribute: Some dogs eat grass due to curiosity, boredom, or instinctual behaviour linked to their wild ancestors.

Evidence doesn’t point to a single reason: Research suggests multiple potential reasons, but no one factor can explain it all.

Exercise caution with treated grass: Ensure your dog’s environment is free from chemicals, and consult a vet if grass-eating is excessive.

In conclusion, dogs may eat grass for reasons ranging from dietary supplementation to simple curiosity, and occasional grazing is generally harmless.

Understanding your dog’s behaviour and keeping a watchful eye on any health changes will help ensure that their grass-eating habits remain a normal part of their day-to-day life.

By monitoring your dog’s behaviour and seeking veterinary advice when needed, you can ensure they’re happy, healthy, and well-nourished. Contact Your Vet Online today to discuss any questions or concerns about your dog’s health and behaviour!

Frequently Asked Questions

1. Is it safe for my dog to eat grass?

Answer: In most cases, yes, it’s safe for dogs to eat grass, especially if it’s untreated.

However, avoid letting your dog eat grass that may have been sprayed with pesticides, herbicides, or other chemicals.

If your dog frequently vomits after eating grass or displays other symptoms like lethargy or diarrhoea, it’s best to consult a veterinarian to rule out health issues.

2. Do dogs eat grass because they’re sick?

Answer: Not necessarily.

While some dogs may eat grass when they have an upset stomach, research shows that most dogs do not appear sick beforehand and do not vomit after eating grass.

Grass-eating can also stem from curiosity, boredom, or even just a preference for the taste and texture.

3. Can eating grass indicate a nutritional deficiency?

Answer: There’s no conclusive evidence that dogs eat grass due to a nutritional deficiency, but some experts suggest that low-fiber diets might encourage grass-eating.

Adding a fiber supplement or high-fiber dog food might reduce the behaviour, although this varies by individual dog.

4. Why does my dog vomit after eating grass?

Answer: Grass has a fibrous texture that can irritate the stomach lining, leading some dogs to vomit after eating it.

This may help them feel better if they were experiencing mild nausea.

However, not all dogs vomit after eating grass, and vomiting alone isn’t necessarily a sign of illness if it occurs infrequently.

5. Is grass-eating more common in certain breeds or ages of dogs?

Answer: Grass-eating is observed across all dog breeds and ages, but younger dogs and puppies may be more prone to the behaviour due to curiosity.

Older dogs with digestive sensitivities or boredom may also eat grass more frequently, although this can vary widely.

6. What can I do to stop my dog from eating grass?

Answer: If you want to discourage grass-eating, make sure your dog is getting enough mental and physical stimulation, as boredom can drive the behaviour.

Adding fiber to their diet or providing chew toys may also help.

Additionally, teaching a “leave it” command can redirect their attention.

If grass-eating is a concern, consult our vets for tailored advice.

7. Should I be concerned if my dog is eating grass every day?

Answer: Daily grass-eating can be normal, but if it’s excessive or accompanied by symptoms like vomiting, diarrhoea, or lethargy, it would be worth discussing with a veterinarian.

Routine grass-eating could indicate a behavioural habit, boredom, or, less commonly, an underlying medical issue.

8. Do wild dogs or wolves eat grass, too?

Answer: Yes, wild canines like wolves occasionally eat grass and other plants as part of their natural diet.

This behaviour likely helps them ingest residual prey material or keeps their digestive tract balanced, supporting the theory that grass-eating may be an instinctual behaviour in domestic dogs.

9. Can I give my dog vegetables instead of letting them eat grass?

Answer: Yes, offering dog-safe vegetables like zuchinni, green beans, or cabbage can provide a low calorie fiber boost and might reduce their interest in eating grass.

However, not all dogs will eat vegetables, and you should avoid giving them foods toxic to dogs, like onions, garlic, or avocado.

10. How can I tell if my dog’s grass-eating is a symptom of something more serious?

Answer: If your dog’s grass-eating is paired with frequent vomiting, lethargy, weight loss, loss of appetite, or diarrhoea it may indicate a health issue.

11. What should I do if my dog ingests grass treated with chemicals?

Answer: If your dog has eaten chemically treated grass, contact your veterinarian immediately, as certain pesticides and herbicides can be toxic.

Try to determine what type of chemical was used and bring any packaging to the vet if possible.

Symptoms of toxicity may include drooling, vomiting, lethargy, and seizures.

In such cases, a veterinary check-up can help determine if there’s an underlying problem, like gastrointestinal upset, infection, or a more serious metabolic disorder.