Is Eating Grass Normal?

You may have seen your dog or cat eating grass and other plants of no apparent nutritional value. Do animals eat grass because they’re sick or have a dietary deficiency? Dr. Karen Sueda, Dr. Kelly Cliff, and myself recently conducted three surveys of pet owners to find answers to these questions about plant eating in pets.

FINDING THE ANSWERS
First, we surveyed veterinary students who owned 25 dogs. All the students reported their dogs ate grass. None reported observing signs of illness before their dogs ate grass, and only 8% said their dogs regularly vomited afterward.

Next, we surveyed 47 dog owners who had brought their dogs to our veterinary hospital for outpatient care. Of this group, 79% had observed their dogs eating plants, usually grass. Thirty-three of the owners answered questions about their dogs’ behavior before and after eating plants. Of these owners’ dogs, only four showed signs of illness and just six vomited afterward.

Finally, we conducted a Web-based survey in which we collected 1,571 usable responses from owners of plant-eating dogs. Our findings showed that:

• 68% of dogs ingest plants on a daily or weekly basis,
• 8% of dogs frequently show signs of illness before plant eating,
• 22% of dogs regularly vomit after eating plants,
• Of the plant-eating dog population, younger dogs eat plants more often than older dogs and are less likely to appear ill before or to vomit after.

In all the surveys, we asked questions about dogs’ diets. There was no indication that dogs fed primarily table scraps or raw food were more prone to grass eating than those receiving a commercial, nutritionally balanced diet. Nor was there any indication that dogs receiving less fiber in their diets tended to eat more plants.

So contrary to the common perception that grass eating is associated with observable signs of illness and vomiting, we found that it is a common behavior in normal dogs unrelated to illness and that dogs do not regularly vomit afterward. Vomiting seems to be incidental to, rather than caused by, plant eating.

WHAT ABOUT CATS?
In an ongoing study with my colleagues Drs. Sueda, Melissa Bain, and Gretel Torres de la Riva, preliminary findings suggest plant eating is less common in cats than in dogs. As in dogs, cats typically are not ill before eating plants nor do they regularly vomit afterward. Our preliminary data suggest that cats eat more nongrass plants than do dogs.

THE BOTTOM LINE
Eating grass is fairly typical. Plant consumption is not usually associated with illness but instead may be a trait inherited from pets’ wild ancestors, such as wolves and wild African Cats, where it helped purge parasites. Still, let your veterinarian know if you see a big change in your pet’s plant eating since this could signal gastrointestinal upset. Also, if your pet has a tendency to eat grass, be sure to keep it away from chemically treated lawns.

TOXIC PLANTS PETS SHOULD AVOID
While flowers and plants look beautiful, some can cause serious illness in pets when eaten. To keep your home safe for pets, here are a few of the common toxic house plants to avoid.

• Lilies, such as the Peace Lily
• English Ivy
• Sago palm
• Cyclamen
• Amaryllis
• Schefflera
• Aloe
• Madagascar Dragon Tree
• Snake Plant
• Yucca
• Hosta

For a cat-friendly indoor green space, consider getting a small grass garden. With grass readily available, your cat will tend to avoid other house plants that might be toxic.