Why Eating Grass Can Be Dangerous To Your Dog

Some of us have dogs that nosh on grass like a starving dieter at a salad bar. The question is, why do they eat grass and why can it be dangerous?

A common theory, one I’ve heard since I was a kid, is that dogs eat grass as a form of self-medication. They have a tummy ache; eating the grass causes them to vomit; and, voila! They feel better.

It’s a theory that seems to make sense on the face of it, but it’s not been found to be valid. In fact, studies have found that eating grass in order to throw up due to a tummy ache is actually quite rare — fewer than 25 percent of dogs vomit after eating grass and only 10 percent showed signs of illness beforehand.

You also may have heard that dogs eat grass in order to make up for some kind of dietary deficiency. Again, no support for this theory has been found. Studies have shown that dogs who had their diet regularly supplemented by plant matter (vegetables or fruit) were no less likely to eat grass.

So, you may be wondering, why do they eat grass?

It’s believed that some dogs eat grass because they find it tasty. Other dogs may eat it out of boredom. Another theory is that grass eating may reflect an innate predisposition inherited from dogs' wild ancestors.

Regardless of the reason, it’s quite common for dogs to eat grass. It’s usually considered a normal behavior by veterinarians.

The reason that grass eating can be dangerous is due to our culture’s affinity for using fertilizers, pesticides, and herbicides on the grass itself. These products are highly toxic, even more so to dogs than to humans because their bodies are so much smaller that these poisons end up in far more concentrated proportions. Many public parks use chemicals, as do many of your neighbors and, perhaps, even yourself. And even healthy grass may be right next to weeds and flowers that are toxic to canines.

If you’re afraid that your dog may be suffering from poisoning caused by lawn treatments, call the ASPCA’s 24/7 Animal Poison Control hotline.