Why Do Dogs Eat Grass? Helpful Information For Pet Parents

Does your dog sporadically snack on grass? There’s a technical term for that: the impulse to eat non-food substances (like grass) is called pica (pronounced ʹpī-kə). And it’s quite common in dogs. 

Is eating grass bad for your dog? The simplest answer is no. But even though eating a little grass from time to time is unlikely to do your dog any harm, it’s a habit that’s best discouraged. Eating grass can expose your dog to harmful toxins and diseases, and in some cases it may reveal an underlying health condition.

Why Do Dogs Eat Grass?

It’s a very common habit, especially in younger dogs. In one survey of 1,500 dog owners, 68% said their dogs ate plants (usually grass) at least weekly or even daily. Below are some possible reasons your pup may engage in this behavior.

Natural Instinct

Dogs are neither strict carnivores nor true omnivores. The wild cousins of domestic dogs (wolves, coyotes, foxes, and other members of the Canidae family) are scavengers, hunting for prey but also eating plants. Research on wolves, for example, has found that grass is a normal part of their summer diet.

Nutritional Deficiency

If your dog eats grass on a regular basis, it may indicate a nutrient deficiency. Pica has been associated with dietary deficiencies in iron, calcium, zinc, thiamine, niacin, vitamin C, and vitamin D.

Grass may provide small amounts of vitamins and minerals, but it’s even more important as a source of fiber. Adequate fiber in a dog’s diet is important for healthy digestion and stool formation.

Behavioral Factors

Some dogs may just like the taste or texture of grass. Other dogs may eat grass for psychological reasons—because they’re bored, anxious, or trying to get your attention.

A 2019 study in Japan found that younger dogs and neutered dogs were more likely to eat non-food items. These groups are often the ones who get bored more easily.

Do Dogs Eat Grass to Induce Vomiting?

The widespread belief that dogs eat grass to induce vomiting if they’ve eaten something bad isn’t backed up by any conclusive evidence. 

In a 2008 study that examined plant eating in dogs, only 1 in 4 dogs vomited after eating grass, and fewer than 1 in 10 showed signs of feeling unwell before eating grass. The researchers concluded that grass eating is a normal behavior in domestic dogs and is not specifically associated with vomiting. 

When dogs do vomit after eating grass, they usually show signs of feeling unwell beforehand. This finding suggests that the cause of the vomiting is less likely the grass itself and more likely the dog’s already upset stomach (and whatever originally caused it). 

If your dog appears to be experiencing nausea before eating grass or regularly vomits after eating grass, it could be a sign of inflammatory bowel disease (IBD) or another serious health condition. Talk with your veterinarian (DVM) to learn more.

Signals from the Gut Microbiome

Your dog’s gastrointestinal tract is lined with billions of bacteria—collectively called the gut microbiome—that play an important role in their overall health, impacting everything from digestion to immunity to mood. 

Those bacteria in a dog’s digestive system communicate with the dog’s brain (and vice versa) through a system called the “gut-brain axis.” Gut bacteria can release hormones, neurotransmitters, and other important chemicals to signal to the dog’s brain what they need. 

When there aren’t enough beneficial bacteria in the gut, or the ones that are present aren’t getting enough of the food they need, the gut bacteria sound the alarm. Through the gut-brain axis, they can signal that they need more nutrients to grow their populations.

Because fresh grass is rich in dietary fiber that helps good bacteria grow, a dog may eat grass in response to an urge originating from their gut bacteria.

Why Eating Grass Can Be Risky

For a healthy dog, eating a little grass from time to time isn’t likely to do any harm. But a grass-eating habit can put your dog at risk of ingesting other, more harmful things.

• Grass that’s been treated with fertilizers, pesticides, herbicides, or other toxic chemicals can poison your dog and make them sick.
• If slugs or snails have traveled through the grass, your dog could become infected with lungworm. 
• Grass is often contaminated with fecal residue from dogs and other animals, which can contain parasites, bacteria, and viruses. Your dog could pick up intestinal parasites – like hookworms or roundworms – or even pathogens like parvovirus.
• Even if you’re confident the grass your pup is snacking on is dog-safe, you don’t want them to develop a habit of eating greenery, because they could one day eat a toxic plant.

Does your dog eat poop? Click here to learn about this behavior (coprophagia), which is also common in dogs. It turns out dogs eat poop for many of the same reasons they eat grass!

How to Stop Your Dog from Eating Grass

Even if a little grass is unlikely to do any harm, it’s safer for your dog not to get into the habit of eating grass or other plants. Here are some ways to break the habit.

Increase Dietary Fiber

In many cases, grass-eating behavior can be reduced or resolved by switching the dog to a higher-fiber diet. One simple way to increase the fiber in your dog’s diet is to mix additional fiber into their regular food. For example, AnimalBiome’s Complete Fiber Blend supplement contains a specially-chosen spectrum of fibers that ferment throughout the digestive tract.

Fructooligosaccharides, or FOS for short, are one type of tiny soluble fibers that are prebiotic, meaning they are the preferred food of beneficial microbes in your dog’s gut. By feeding the beneficial bacteria, fibers like FOS help restore balance to the bacterial communities in the gut, improving both gut health and immune function. 

Your dog can get a healthy dose of FOS from AnimalBiome’s S. boulardii + FOS probiotic/prebiotic powder.

Talk to your veterinarian about whether your dog’s diet provides sufficient fiber.

Enforce New Behaviors

Pulling your dog away from a patch of grass may actually make the forbidden thing even more enticing. But there are other ways to reduce a grass-eating habit.

• Arrange to take your walks after your dog has had a meal, so they’re less likely to eat grass out of hunger.
• It’s difficult for a dog parent to avoid grass completely, but if your dog has a favorite patch of grass to graze on, avoid that area for a few weeks to break the habit. 
• If you think your dog is eating grass because they’re bored, try redirecting their attention with a toy, food puzzle, or walk. Boredom is often a sign that dogs need more play, mental stimulation, and exercise, and it’s especially common in younger dogs and more active breeds.
• If you think your dog is eating grass as an attention-seeking behavior or because they’re anxious, reassure your four-legged friend with extra affection. You can also comfort a dog who gets anxious when you’re away by giving them an old T-shirt with your scent. 

Provide Microbiome Support

A properly functioning gut microbiome is crucial for a healthy pet. This complex community of gut microbes helps with digestion, disease prevention, nutrient absorption, and immunity. 

Many variables can affect a dog’s gut microbiome, including diet, antibiotics, and genetics. Once you’ve confirmed that you’re feeding the best diet for your dog’s gut health, the next step is to determine whether their microbiome is balanced.

Microbiome testing is a useful tool for identifying any bacterial imbalances that may be present in your dog’s gut. It can also tell you which specific dietary adjustments may improve your dog’s gut health. For example, if your dog’s test reveals low levels of Fusobacterium, a type of bacteria that digests animal proteins, you may be advised to increase the amount of protein in their diet. 

Some gut imbalances can be resolved with diet changes alone, but there are many ways to restore your dog’s gut health if their microbiome is imbalanced. 

You’ve probably heard of probiotics: These strains of beneficial microbes can be found in fermented foods (like yogurt and sauerkraut) and in certain supplements. Prebiotics and postbiotics are different from probiotics, but are just as important for maintaining a healthy gut microbiome. 

Learn more about pro-, pre-, and postbiotics here.

Key Takeaways

• Dogs eat grass for a variety of reasons, and there are many ways dog parents can help them break the habit. 
• Eating grass because of a nutrient deficiency can be addressed with dietary changes and fiber supplementation. 
• Eating grass because of boredom or behavioral issues can often be resolved through positive reinforcement techniques, more play, and more exercise. 
• AnimalBiome offers numerous resources and products to help you support your dog’s gut health. 
• Work with your veterinarian to rule out any underlying health problems that could be causing your dog’s grass-eating habit, especially if the behavior is accompanied by vomiting, nausea, or belly pain. 

FAQ

Does a dog eating grass mean anything?
Yes! From boredom to nutrient deficiencies, eating grass is a sign that something could be going on with your dog’s health. 

Why is my dog suddenly eating a lot of grass?
Your dog might be responding to their body’s need for fiber or nutrients they’re not getting from their current diet. 

Do dogs eat grass to settle their stomachs?
There is currently no strong evidence indicating that dogs eat grass to resolve nausea or induce vomiting. 

Does eating grass mean my dog has worms?
No. There’s no evidence that having worms causes dogs to eat grass.

Should I let my dog eat grass when they’re sick?
If your dog is feeling unwell, consult your veterinarian. (Eating grass won’t help.)

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