Why Do Dogs Eat Grass? (And When Should You Worry?)

One minute, your dog is happily trotting through the park. The next, they’re munching on grass like a tiny cow. If you’ve ever wondered, "Why is my dog eating grass?" - you’re not alone.

Grass-eating is one of the most common (and mysterious) dog behaviours, and while it’s usually harmless, sometimes it can signal an underlying issue. So, is your dog craving a salad, soothing an upset tummy, or just being weird? Let’s find out!

Why Do Dogs Eat Grass? Theories and Science

There’s no single answer, but experts have a few leading theories about why dogs enjoy a good lawn snack:

1. It’s in Their DNA

• Dogs are omnivores, meaning they eat both meat and plants.

• Wild canines like wolves sometimes eat grass and plants, so it could be an instinctive behaviour passed down through generations.

2. They’re Just Curious (Or Bored!)

• Some dogs eat grass simply because it’s there—especially puppies who explore the world with their mouths.

• Boredom can also lead to random grazing, particularly if they don’t have enough toys or activities.

3. They Like the Taste or Texture

• Some dogs genuinely enjoy chewing on grass. The texture, smell, and even the moisture content might be appealing.

• Certain grasses may be more tempting than others—your dog might have a "favourite flavour" of grass!

4. Tummy Trouble Relief

• Many owners assume dogs eat grass to make themselves vomit, but research suggests fewer than 25% of dogs actually throw up after eating grass.

• However, some dogs with upset stomachs may instinctively eat grass as a form of natural relief.

5. Nutritional Deficiencies

• If a dog’s diet is lacking fibre, they may seek out grass as a supplement.

• While this is rare in dogs on high-quality food, it can happen—especially if they’re on a highly processed diet.

When Should You Be Concerned About Grass-Eating?

Most of the time, munching on grass is completely normal, but there are a few red flags to watch for:

🚨 1. If They’re Eating Grass Obsessively

• Occasionally snacking? Normal.

• Non-stop grazing every time they go outside? That might signal an underlying health issue like nausea or anxiety.

🚨 2. If They Vomit Every Time After Eating Grass

• A one-off? Probably not a big deal.

• Repeated vomiting could indicate gastrointestinal issues, parasites, or food intolerances.

🚨 3. If the Grass Has Been Treated with Chemicals

• Pesticides, herbicides, and fertilisers can be toxic to dogs.

• Always check that grass is chemical-free before letting your dog munch away.

🚨 4. If They Show Other Symptoms

• Diarrhoea, lethargy, or loss of appetite alongside grass-eating? Time for a vet visit.

• This could be a sign of gut problems, worms, or even something more serious.

How to Stop Your Dog From Eating Grass (If Needed)

If your dog’s grass-eating habit is worrying you, here are some ways to curb it:

✔️ Provide More Fibre in Their Diet

• Adding pumpkin, sweet potato, or leafy greens to their food might reduce their need for grass.

• High-quality dog food should already contain enough fibre, but if in doubt, chat with your vet.

✔️ Increase Mental and Physical Stimulation

• Bored dogs often resort to weird behaviours (including eating grass!).

• Try longer walks, puzzle feeders, interactive toys, or playtime to keep them engaged.

✔️ Supervise Outdoor Time

• If your dog is a grass fanatic, keep an eye on them while outside.

• Redirect their attention with a toy or game if they start grazing.

✔️ Train a “Leave It” Command

• Teaching “Leave it” can help prevent unwanted snacking.

• Reward them with a treat when they choose not to eat the grass.

✔️ Provide Safe, Dog-Friendly Greens

• If your dog enjoys munching on greens, try growing pet-safe plants like wheatgrass.

Fun Fact: Some Dogs Just Like Eating Grass, and That’s Okay!

Not every behaviour needs a serious explanation—sometimes, dogs are just being dogs! If your pup occasionally enjoys a little grassy treat, isn’t vomiting, and has a healthy diet, it’s usually nothing to worry about.

When to See a Vet About Grass-Eating

📌 Book a vet visit if your dog:
✔️ Vomits frequently after eating grass.
✔️ Eats grass obsessively, not just occasionally.
✔️ Shows signs of nausea (drooling, lip licking, swallowing excessively).
✔️ Has diarrhoea, lethargy, or loss of appetite.
✔️ Eats grass from areas treated with chemicals.

Final Thoughts: Should You Let Your Dog Eat Grass?

✅ Yes, if:

• They only eat grass occasionally.

• They seem otherwise happy and healthy.

• The grass is free of pesticides and chemicals.

❌ No, if:

• They vomit every time after eating it.

• They eat grass compulsively.

• There are signs of illness or distress.

At the end of the day, a little bit of grass-munching is usually harmless - just another quirk in our dogs’ endless list of funny behaviours!