WHY DOGS EAT GRASS?

If your dog stops during a walk to munch on a patch of grass, you’re not alone in wondering why. Many pet owners assume it means their dog has an upset stomach and is trying to make itself vomit. However, research suggests that’s usually not the case.

Eating Grass Is Normal

Grass-eating is a very common behaviour in dogs. Studies have found that around three out of four dogs eat grass regularly, making it a perfectly normal habit for most healthy dogs. 

It’s Usually Not Because They’re Sick

Contrary to popular belief, most dogs do not eat grass because they feel unwell. Research has shown that only a small percentage of dogs appear ill before eating grass, and even fewer vomit afterwards.

Scientists have also found no evidence that dogs eat grass to make up for a nutritional deficiency. Dogs fed different types of diets—including kibble, raw food and vegetarian diets—were all equally likely to graze.

They May Simply Enjoy It

The simplest explanation is often the most likely: many dogs seem to enjoy eating grass. Some even show a preference for fresh, tender grass, especially in the early morning, suggesting they find it appealing rather than using it as a remedy.

An Instinct from Their Wild Ancestors?

Researchers believe grass-eating may be an inherited behaviour passed down from dogs’ wild ancestors. One theory suggests that plant material may once have helped wild canids remove intestinal parasites, although there is currently no conclusive proof.

The exact reason dogs developed this habit remains uncertain, but experts agree that it appears to be a normal instinctive behaviour rather than a sign of illness.

When Should You Be Concerned?

While occasional grass-eating is usually harmless, it may be worth speaking to your veterinarian if your dog:

• Suddenly starts eating large amounts of grass.
• Appears unwell before eating grass.
• Vomits frequently after grazing.
• Becomes obsessed with eating grass or other non-food items.

It’s also important to prevent your dog from eating grass that has been treated with pesticides, herbicides or fertilisers, and to keep them away from toxic plants.

The Bottom Line

For most dogs, eating grass is simply a normal part of being a dog. As long as your pet is otherwise healthy and the behaviour isn’t excessive, there’s usually no reason for concern. Sometimes, that patch of fresh grass is simply an enjoyable snack.