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Ask the Vet: Why is My Dog Eating Grass and Vomiting?

Dog Eating Grass and Vomiting

Have you ever wondered where does your dog’s irresistible urge to nibble on grass, come from? And why he does that? The technical term used to describe the habit of eating things that are not food is pica. In some cases, pica can be considered an alarm that signals some sort of nutritional deficiency. In other cases it is a simple sign of boredom or playful behavior. Boredom-induced pica is particularly common among puppies and younger dogs.

The menu for dogs with pica is endless – dirt, wood, stones, sand…but what about grass? Is eating grass considered an actual disorder? The simple answer is no. Both wild and domesticated dogs have been observed to eat grass. As a matter of fact, veterinarians accept this canine behavior as perfectly normal. Additionally, a recent study showed that grass is the most commonly eaten plant by dogs.

Is your dog eating grass and vomiting?

Is your dog eating grass and vomiting?

Why is My Dog Eating Grass and Vomiting?

If you google the question, why do dogs eat grass, you will be faced with more than two million answers. However, if you search for scholarly articles on the subject, the search results list will be almost empty. This is because none of the potential answers is scientifically proven.

It is a popular belief that dogs eat grass to induce vomiting. In a nutshell, when a dog’s stomach is upset, the dog eats grass. The grass blades tickle the throat and lining of the stomach. The ticklish sensation triggers the vomiting.

What is more, dogs gulp down the grass rather than chewing it thus increasing the intensity of the ticklish sensation. If the ticklish sensation is not enough, the fact that the dog’s stomach is not designed to process plants will do the trick. While vomiting, the dog gets rid of the hard-to-digest grass and hopefully of the irritating agent that disturbed the stomach in the first place. Once the underlying cause has been thrown up, the dog will feel better.

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However, recent studies show that most dogs are not unwell before eating grass or at least they are not showing any signs of sickness. To be more accurate, according to their owners, less than 10 percent of the dogs included in the study seemed to be sick before the grass eating session. In addition, grass eating does not always result in vomiting. In fact, less than 25% of the dogs that graze on grass actually vomit.

5 Theories Why Dogs Eat Grass

Taking into consideration the above stated facts, it is only logical to search for other reasons why dogs eat grass. The most popular theories include:

  • Eating grass improves the digestion process by purging the gastrointestinal tract.
  • Eating grass helps combat intestinal worms. Wild chimpanzees consume plant material in order to increase their intestinal motility and consequently promote elimination of intestinal parasites. There is no reason to believe that dogs are not using the same trick.
  • Eating grass helps fulfill certain unmet nutritional needs. It has been shown that dogs with fiber deficient diets tend to eat grass on a regular basis. Once switched to high-fiber diet their grass eating behavior stops.
  • Dogs like the taste and texture of grass.
  • Eating grass is written in the canine DNA and a remnant of wild dogs’ behavior. It is assumed that prior to domestication, dogs hunted small, grass-eating animals such as birds, rodents and smaller mammals and when consuming them whole, they would receive green nutrients through the content of their prey’s digestive tract.
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All in all, there is no solid evidence that grass eating and self-curing are directly linked.

What Causes Dogs to Eat Grass and Vomit?



As a responsible parent of a grass-eating canine baby you should be interested in determining the underlying cause of this habit.

The investigation starts with answering three simple questions: Is my dog a voracious grass eater? Does my dog vomit or feel sick before and after eating grass? Is there a pattern in my dog’s grass eating behavior?

If the answers to the first two questions are no, then there is no room for panic. If the answers are yes, then question number three should be carefully examined and a visit to the vet’s office should be scheduled.

The vet will take your dog’s full history and then perform a thorough physical examination. To get down to the bottom and determine the exact cause, the vet is likely to order some additional tests like:

  • Blood work (complete blood count and biochemistry profile)
  • Fecal analysis
  • Urinalysis
  • Abdominal radiography (with or without a contrast)
  • Abdominal ultrasound
  • CT scan
  • Endoscopy
  • Biopsy
  • Exploratory laparoscopy.

Dealing with Dogs Eating Grass and Vomiting 

If the vet determines there is no medical background to your dog’s grass consuming habit, you are faced with four options:

  1. Train your dog not to eat grass. This alternative is successful in food oriented dogs that can be offered other treat rewards and dogs that respond to positive verbalization and petting.
  2. Ignore the behavior while ensuring the grass is not chemically treated. Eating grass may not be dangerous, but most pesticides used for grass treatments are toxic to dogs and if consumed can have lethal consequences.
  3. Discourage the grass consuming behavior. This can be achieved through keeping the grass short and installing water sprinkles.
  4. Accept your dog and all the peculiarities that come along with being a dog parent. You can even go the extra mile and create a special grazing area for your dog. The area should be planted with dog-friendly grass that is free of chemicals.

About the Author 

Dr. Ivana Crnec is a graduate of the University Sv. Kliment Ohridski’s Faculty of Veterinary Medicine in Bitola, Republic of Macedonia.

ivana crnec

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