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The Unexpected Reason Dogs Sometimes Eat Grass And Then Vomit

By: Ejay Camposano
A college graduate with a degree in Electrical Engineering, Ejay has a diverse background that combines technical expertise with a passion for pets and is now one of the content writers at IHD. Read more
| October 7, 2024

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If you’ve ever seen your dog munching on grass only to throw it up moments later, you’ve probably wondered what on earth they’re doing. This odd behavior can be alarming, especially when your dog seems perfectly healthy otherwise. It’s not uncommon for dogs to eat grass, but what’s surprising to many owners is the immediate vomiting that often follows. While it may seem counterproductive, there are several reasons why dogs engage in this peculiar habit. The reasons behind grass-eating and vomiting are more complex than they appear.

A Natural Way to Induce Vomiting

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One of the most common explanations for why dogs eat grass is that they do it to make themselves vomit. Dogs sometimes eat things they shouldn’t—whether it’s a piece of garbage or something they found on the ground—that can upset their stomach. Eating grass can irritate the lining of their abdomen, which triggers vomiting and helps them expel whatever is making them feel ill. In this case, eating grass is a form of self-medication, allowing the dog to clear their digestive system and feel better afterward.

Grass May Help Soothe Upset Stomachs

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Another theory is that dogs eat grass to soothe an upset stomach. Just as we might reach for ginger ale or crackers when we’re feeling queasy, dogs may instinctively turn to grass for relief. The fibrous texture of grass can help absorb excess stomach acid, providing temporary relief from indigestion. Although vomiting often follows, the act of eating grass might help settle their stomach for a moment before the nausea passes. This could explain why some dogs seem to eat grass only when they aren’t feeling their best.

An Instinct Passed Down From Their Ancestors

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Dogs have evolved from wolves and other wild canines, and some behaviors, like eating grass, maybe leftovers from their ancestors. In the wild, wolves and wild dogs often consume plants and grasses along with their prey. These plants can help with digestion, add fiber to their diet, or even act as a natural dewormer. While domesticated dogs no longer need to rely on grass for nutrition, the instinct to eat grass may still be hardwired into their behavior. Vomiting afterward could simply be a side effect of this ancient habit.

Seeking Fiber for Digestive Health

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Dogs don’t always get the ideal amount of fiber from their regular dog food, especially if they’re eating a diet that’s low in plant-based ingredients. Grass is rich in fiber, and some dogs might turn to it as a natural source to help improve their digestion. Just like humans need fiber to keep their digestive system functioning properly, dogs may seek out grass when they’re feeling constipated or bloated. While vomiting might occur after eating grass, the initial goal could be to add fiber to their diet and help regulate bowel movements.

A Boredom Buster

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For some dogs, eating grass is simply a way to pass the time. Dogs are naturally curious creatures, and if they’re bored or under-stimulated, they might turn to whatever is available in their environment—including grass. Dogs that spend a lot of time outside or in a yard with limited toys or interaction might start munching on grass as a way to entertain themselves. Vomiting may be an unfortunate consequence of this behavior, but the primary motivation in these cases is likely boredom rather than an upset stomach.

Attention-Seeking Behavior

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Dogs are incredibly smart, and they quickly learn which behaviors grab their owner’s attention. If your dog notices that eating grass and vomiting gets a big reaction from you—whether it’s concern, scolding, or extra attention—they might repeat the behavior to get the same response. This isn’t to say that dogs are intentionally trying to make themselves vomit, but they may learn that eating grass leads to increased attention, reinforcing the habit. In this case, the vomiting is incidental, and the real motivator is the extra focus and care they receive afterward.

Curiosity About Their Environment

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Dogs explore the world primarily through their noses and mouths, and sometimes eating grass is just another way of investigating their surroundings. Just like puppies chew on shoes or random objects, adult dogs may chew on grass out of curiosity. Grass is readily available, and some dogs might be intrigued by its texture, smell, or taste. Unfortunately, this exploratory behavior can sometimes result in vomiting, particularly if they overeat or their stomach doesn’t agree with the grassy snack.

Stress or Anxiety

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Stress or anxiety can also lead to grass-eating in dogs. Dogs that are feeling anxious may engage in repetitive or compulsive behaviors, and eating grass might be one way they cope with their feelings. If your dog tends to eat grass more frequently during stressful situations—like after moving to a new house, meeting new people, or during thunderstorms—it’s possible that they’re using the behavior as a way to self-soothe. The vomiting that follows could be a result of overeating the grass in an anxious state.

Nutritional Deficiency

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While most dogs receive all the nutrients they need from commercial dog food, some might instinctively eat grass as a way to supplement a nutritional deficiency. For example, if a dog’s diet is lacking in certain vitamins, minerals, or fiber, they may eat grass to compensate. The nutrients found in grass, while not substantial, could provide something the dog feels is missing from their regular meals. In these cases, vomiting might occur if the dog overeats grass in an attempt to get those missing nutrients.

It’s a Natural Part of Scavenging Behavior

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Dogs are natural scavengers, and in the wild, they consume a variety of things to meet their nutritional and survival needs. Eating grass could be part of this scavenging instinct, as it mimics the behavior of foraging for food. Wild canines often eat entire animals, including the stomach contents, which may include grasses and plants. While domesticated dogs no longer need to scavenge for food, the instinct to consume grass may remain, even though their modern diet provides all the nutrients they need.

A Matter of Taste or Texture

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For some dogs, eating grass might be as simple as enjoying the taste or texture. Just like humans have food preferences, dogs can be drawn to the taste or feel of grass in their mouths. While it may not seem appetizing to us, the cool, crisp texture of grass could be appealing to a dog, especially on a warm day. Unfortunately, the digestive system of dogs isn’t always equipped to handle grass in large quantities, which can lead to vomiting shortly after they indulge in their grassy snack.

Grass: Nature’s Salad or Your Dog’s Worst Frenemy?

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Ever feel like your dog treats grass like a gourmet snack, only to immediately regret their decision by throwing it up on your favorite rug? It’s almost as if they see grass as nature’s ultimate salad—healthy in theory but sometimes a bit disastrous in practice! While the reasons for dogs eating grass can vary, from soothing an upset stomach to pure curiosity, one thing is certain: they have their reasons, even if they leave you scratching your head (and scrubbing the carpet). Dogs sure know how to keep life interesting!