If you’ve ever caught your dog munching on grass during a walk or in the backyard, you’re not alone.

6/2/2025 | Sniff & Bark

Many dog parents wonder, “Why does my dog eat grass?” It’s a classic dog mystery that has puzzled pet owners for centuries. Is it a sign of illness? A nutritional need? Or just quirky behavior? Let’s dive into the research and science behind this curious canine habit.

Grass Eating: Is It Normal or Cause for Concern?

First off, the good news: grass eating is generally normal and common in dogs. Studies show that anywhere from 25% to 80% of dogs engage in grass consumption at some point. It’s not usually a sign of sickness, though there are exceptions.

What Does Science Say?

Veterinarians and animal behaviorists have offered several evidence-based explanations for why dogs might eat grass:

1. Ancestral Instinct and Natural Diet

Dogs descend from wild ancestors—wolves and other wild canines—that had a varied diet, including plant material found in the stomachs of their prey. Research suggests that eating grass could be a natural instinct inherited from their wild ancestors to supplement their diet with fiber and micronutrients.

• Fiber intake: Grass contains cellulose, which provides roughage to help digestion and maintain bowel health.

• Micronutrients: Some grasses are rich in chlorophyll, vitamins (like folate), and minerals that could benefit gut health.

2. To Aid Digestion or Relieve Stomach Upset

Many dog owners believe their dogs eat grass when feeling nauseous or experiencing digestive discomfort. Studies back this up to some degree:

• Research published in Veterinary Medicine indicates that some dogs may eat grass to induce vomiting if they feel queasy.

• However, not all grass-eating dogs vomit afterward, which means this behavior isn’t always a sign of sickness.

3. Boredom, Anxiety, or Attention-Seeking

Behavioral science also points to environmental or emotional reasons behind grass eating.

• Dogs left alone or under-stimulated may chew grass out of boredom.

• Grass eating can be a displacement activity when a dog is anxious or stressed.

• Some dogs learn that eating grass gets attention from their owners, reinforcing the habit.

4. Nutritional Deficiencies

Though less common, some experts suggest grass eating might be a sign of a nutritional deficiency, such as lacking fiber, vitamins, or minerals in their diet.

• If your dog frequently eats grass and shows other signs of poor health, consulting your vet for a nutritional checkup is wise.

When Should You Be Concerned?

While grass eating is often harmless, watch out for these signs that warrant a vet visit:

• Excessive or compulsive grass eating

• Frequent vomiting or diarrhea

• Signs of pain or distress

• Changes in appetite, energy, or behavior

Some Tips for Dog Parents: Managing Grass Eating

• Provide a well-balanced, fiber-rich diet tailored to your dog’s needs.

• Ensure plenty of physical exercise and mental stimulation.

• Offer safe chew toys to reduce boredom-driven grass chewing.

• Keep an eye on the types of grass and plants accessible, avoiding toxic species or pesticides.

What Grass Eating Means for Your Dog

Grass eating is a surprisingly normal and often instinctual behavior in dogs. Whether it’s driven by ancestral diet habits, digestion, boredom, or nutrition, it’s rarely a cause for alarm. By understanding why your dog eats grass, you can better support their health and happiness.