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Why Do Dogs Eat Grass? (Hint, it’s Not What You Think)

why do dogs eat grass

Have you ever seen your dog eating grass? If you’re like us, you might have thought that eating grass soothes an upset tummy, or that dogs eat grass to make themselves sick. Although grass does contain irritants that induce vomiting, research suggests dogs are less likely to eat grass when they’re sick. So, what’s going on? Why do dogs eat grass?

8 Reasons Why Dogs Eat Grass  

The scientific research on dogs eating grass is scarce, yet theories exist. We can discount some theories based on the few studies we have so far. This is what the research suggests.  

1. They are hungry  

One study linked grass eating in dogs to their levels of hunger on that day. The research showed dogs spent more time eating grass before consuming a bowl of kibble than after the meal. Therefore, grass eating could just be a sign your dog is peckish.  

2. It’s natural behaviour  

We think of dogs as carnivores, and it’s true, their diet consists mainly of protein from meat sources, but they are actually omnivores. This means they eat meat and plants. Dogs evolved from wolves, and plant material accounted for up to 10% of their wolf ancestor’s diet. So, eating grass is quite natural.  

3. They are curious and exploring their environment  

Dogs use different senses to humans to explore their surroundings. Much like babies put everything in their mouths when examining new objects, so do puppies and younger dogs.   

4. Dogs like the taste of grass  

Grass eating increases between April and August. Experts believe the taste, smell and texture of grass changes during these months, making it more alluring for dogs.   

5. Dogs eat grass because they’re bored  

Experts attribute some repetitive or unusual behaviour in dogs to boredom. If you’ve noticed your dog chewing, barking or misbehaving more, and eating grass, it could be a sign they’re lacking mental or physical stimulation.   

6. Dogs eat grass to add fibre to their diet  

Grass has little nutritional value, but it has fibre. One study in 2007 showed that increasing the fibre content in a miniature poodle’s diet diminished its daily grass eating and vomiting. Dogs can digest some carbohydrates thanks to living with humans for so long. However, grass is mainly inedible.   

7. Grass eating gets rid of parasites  

Grass is an excellent source of fibre and can help with digestion as it passes through the intestines undigested. It also has the effect of ‘mopping up’ harmful parasites that might otherwise hang around in the gut.   

8. Eating grass is attention-seeking  

Dog owners that react dramatically to eating grass teach their dogs they get attention every time this happens. If you think it’s attention-seeking, try ignoring the behaviour and rewarding them when they don’t do it.  

Now that we know why dogs do eat grass, here’s what research says about dogs eating grass when they’re sick. 

Do dogs eat grass when they are sick? 

Dogs don’t eat grass when they are ill  

Evidence from several studies shows dogs don’t eat grass to induce vomiting or soothe an upset stomach. One study tested two groups of dogs; one group had diarrhea and the other group did not. The results showed the group with diarrhea ate less grass.    

Dogs don’t eat grass to make themselves sick  

Another study recorded the number of times a dog was sick after eating grass. In 709 grass eating incidents, only 5 dogs vomited.     

Should you let your dog eat grass?  

Eating grass is fairly harmless and doesn’t harm the dog, but there are some risk factors


Dirt and poop  

You can find all kinds of dirt and poop in and on grass, so it’s not the most hygienic thing for your dog to be eating. Dogs can pick up diseases like Parvovirus (found in dog poop), which can be fatal. They can also ingest parasites such as worms or fly eggs (yuk).  

Pesticides and chemicals  

Pesticides are poisonous to dogs, so you should be careful about the amount of grass they are eating. And don't forget, councils and private residents might put down substances like rat poison or dispose of harmful chemicals.   

How to stop your dog eating grass  

If you are worried about the amount of grass your dog is eating, here are some tips to stop them: 


  • Walk them after feeding them  

  • Keep them on a lead  

  • Let them eat safe grass (in your garden)  

  • Reward them when they come away from grass  

So, to recap, dogs can eat grass without harm. However, grass can be contaminated, so we advise keeping grass eating to a minimum. 


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