Why Do Dogs Eat Grass?

Written by Small Door's medical experts

Have you ever wondered why your dog eats grass? Many people think it happens when a dog’s stomach is upset. Unfortunately, no one knows for sure why dogs sometimes chow down on grass! But read on to learn more about theories, potential risks and dangers, and how to deal with your pup’s tummy troubles.

In This Article

Theories about why dogs eat grass

There isn’t a scientifically definitive answer to the question of why dogs eat grass. And there aren’t a lot of research dollars being spent on this question, so we may never know for certain!

Some sources claim that dogs eat grass when they need to vomit, but not many dogs—in fact, fewer than a quarter—actually vomit from eating grass. Other theories posit that grass-eating may improve digestion, help with intestinal worms, or fulfill an unmet nutritional need for fiber. Grass does contain some essential nutrients, but even dogs that already have a balanced, nutritious diet will sometimes eat grass. Yet another theory is that eating grass is a compulsive behavior signaling psychological distress.

Scientists point out that wild dogs aren’t strictly carnivores—they’re omnivores that scavenge, hunt, and include plants in their diet. Wild dogs may also ingest plants secondarily, by consuming whatever is in the stomachs of their herbivorous prey. So there’s a good possibility that eating grass is your domesticated pup’s way of making up for the plants that are missing in his kibble.

Is eating grass a physical, nutritional need?

Dogs are not pure carnivores, and in the wild, they consume anything that helps fulfill their basic dietary requirements. It’s thought that some dogs may eat grass to help fulfill their need for fiber. However, not all dogs eat grass, and they can survive perfectly well without grass when they’re fed a nutritionally complete dog food, so it’s unlikely that grass-eating is a physical, nutritional need for most dogs.

Is eating grass a psychological need?

Many domesticated dogs live an anxious life, struggling with separation anxiety or specific anxiety triggers, so eating grass may have a psychological basis; it can be a way to self-soothe and settle boredom.

Do dogs eat grass to vomit?

One widespread theory about grass-eating is that dogs eat grass when they’re feeling sick, to make themselves vomit. However, while some dogs do vomit after eating grass, they don’t always (and in fact, they don’t the majority of the time). Many dogs that eat grass do not display any other symptoms of gastrointestinal distress, so it’s unlikely to be the cause of grass-eating in all cases.

Vomiting is a natural reaction of the gastrointestinal system when it detects something inedible, such as a large volume of grass. If only a small amount of grass has been consumed, your dog is less likely to vomit.

Do dogs like grass?

Dogs may eat grass simply because they like it! The texture or taste may appeal to them, and you may notice your dog eating more grass during the spring when there are more new sprouts around.

Is eating grass dangerous for dogs?

No. In and of itself, eating small amounts of grass does not pose a real risk to your dog, but be aware of what might be on the grass your dog eats. Pesticides, herbicides, and other chemicals can endanger your dog’s health. If your dog isn’t limiting his intake of greenery to simple grass or clover, make sure he’s not nibbling on plants that are poisonous for dogs.

Additionally, dogs who eat grass may ingest parasites like roundworms and hookworms from other animals' fecal matter that has contaminated the grass. If you find your dog is regularly eating grass and suspect an infestation, it’s important to talk to your veterinarian and make sure they’ve been treated with a deworming medication. 

Pay attention if your dog, or more significantly your puppy, is eating a lot of grass. In some cases, it could lead to a life-threatening intestinal blockage, which could require emergency surgery.

In and of itself, eating small amounts of grass does not pose a real risk to your dog, but be aware of what might be on the grass your dog eats.

When should you take action?

You might be wondering, how much grass is too much? If your dog is only eating a small amount of grass every now and then, and doesn’t show any concerning signs, it’s fine to continue allowing them to eat grass if you like.

If they are eating excessive amounts, vomiting frequently, or you suspect their grass eating may be caused by an underlying medical or nutritional issue, it is important to treat this first.

How can I stop my dog from eating grass?

If your dog is eating grass because she’s bored, increase the amount of exercise and playtime your dog is getting each day. You can also provide interactive toys, such as food puzzle toys to provide mental stimulation, especially when they are home alone for longer periods of time. If stress is the issue, try to eliminate triggers, including changes in their routine or environment. Many dogs benefit from having a dedicated ‘safe space’ that they can retreat to when they feel anxious, such as a kennel or crate with a comfy bed and favorite toy. Natural therapies and products can also help with anxiety, including calming aids like pheromone collars (Adaptil) or products like the Anxiety Wrap or Thunder Shirts. For severe stress/anxiety issues, you may need to enlist the help of a behavioral specialist who can assist with techniques such as desensitization and counterconditioning.

If you’re worried that your frequent grass-gobbler is suffering from a nutritional issue, speak to your veterinarian. They can conduct tests to identify specific nutritional deficiencies and advise on a prescription diet or supplements, if needed. (A note on this: if you change your dog’s diet, do so gradually. Your dog will thank you.) On the other hand, if eating grass is only an occasional acute craving, try feeding your dog a few leaves of spinach or basil to see if that satisfies them. You may feel more comfortable giving your pup leaves that you put in your own salad bowl, rather than risk having them eat random greenery outdoors.

You can also discourage grass eating by keeping your dog on a leash outside, or under close supervision, and intervening at the first sign of grass eating. Attempt to distract them from the grass before they eat it with a favorite toy, or by asking them to perform a command they’re familiar with, such as sit, and rewarding them with a treat. If they do eat grass, don’t punish them. Instead, gently lead them away and use the distraction technique mentioned above. You can also use positive reinforcement (praise, pets and treats) when they sniff grass but do not eat it.

Alternatively, you can just let your dog eat small amounts of grass occasionally. It’s not a big deal as long as it’s not causing them to vomit repeatedly.

How do you settle a dog’s upset stomach?

If you’re worried that your dog is eating grass in an attempt to cure an upset stomach, it makes sense to think about what you can do to help.

We recommend withholding food for 12-24 hours, keeping your dog hydrated and taking them out for lots of potty breaks. Then feed a bland diet (such as a small amount of unseasoned boiled chicken and rice) for a couple of days and slowly reintroduce their usual food. 

There are a lot of other home remedies you can try for upset stomachs: plain yogurt, a daily probiotic, pumpkin, oatmeal, and bananas. In some cases, human medicines may be of use, such as Imodium (though you should avoid this if you have a small dog, or a Collie, Shetland Sheepdog, Australian Shepherd or related breed) and Pepto-Bismol. However, to avoid possible complications, ALWAYS check with your veterinarian before giving your dog any OTC “human” medications, as certain medicines are toxic to dogs, and it’s very easy to overdose

Upset stomachs are unpleasant, for both you and your dog, but usually there’s no reason to panic. However, here are a few symptoms that justify a call to the veterinarian:

  • Dehydration. Does your dog have dry, tacky, or pale gums, or low skin-elasticity?

  • Painful, distended, or hard belly.

  • Retching, vomiting, trying to vomit, or difficulty defecating.

  • Blood in vomit, urine, or feces.

  • Lethargy.

  • Diarrhea.

  • Suspected ingestion of chemicals, poisons, medications, toxic foods, or a foreign object.

Summary of why dogs eat grass

Ultimately, there’s no one reason why dogs may it grass. It could be due to anxiety or boredom, nutritional needs, gastrointestinal issues, or simply because they just enjoy it. In most cases, eating grass isn’t something that you need to be worried about, but you should monitor your dog’s grass intake and make sure if they are going to graze, you let them do so in an area where you know how the grass is safe.

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