Why Do Dogs Eat Grass?

The AKC says that dogs eating grass is a common behavior that often surprises owners, especially when it happens during routine potty breaks. While it can be unsettling to watch a dog munch on the lawn, the AKC says grass-eating isn’t always a sign that something is wrong.

Possible reasons dogs eat grass

The AKC says there are a variety of reasons why some dogs can find grass to be a delicacy. These are possibilities the AKC presents — not settled answers for any one dog.

• Instinct. The AKC says that if a dog has a complete and balanced diet, eating grass may not be related to a deficiency at all — it might just be instinct. While canines in the wild weren’t getting their primary source of nutrients from grass, eating an entire animal provided an optimal diet, especially if the animal’s diet consisted of various plants. The AKC says pets may just naturally crave grass as part of their genetic makeup, an echo of their long-ago wild ancestry.
• A need for fiber. The AKC says eating grass could also be a dog’s way of getting more fiber in their diet, which helps them digest their food, pass stool, and generally keep their GI system operating like clockwork.
• Diet deficiency and pica. The AKC says that if a dog’s grass-eating habit is extreme, a vet may advise that it could be a form of pica, a condition where dogs compulsively eat non-food items (often rocks, dirt, or even fabric). The AKC says this condition is sometimes caused by a diet deficiency, and that pica shouldn’t be a problem for dogs who are fed a well-balanced diet.
• Grass acts as an antacid. The AKC tells of a dog that would frantically gobble up as much grass as possible first thing in the morning until she threw up some yellow foam, and was perky after that. Dr. Jerry Klein, AKC Chief Veterinary Officer, says in the article: “Yellow foam, or bile, usually indicates that the dog has an empty stomach. The bile can be very irritating and uncomfortable to the dog’s stomach. People take antacids to ease this pain, but dogs may eat grass to help them release the bile and feel better.”
• Boredom or lack of stimulation. The AKC says that if a dog is hanging in the yard alone and eating grass, it may be that they’re just bored, because most dogs would rather have their owner’s companionship.
• A tasty treat. The AKC says a dog might also just really enjoy the taste and texture of fragrant, wet grass in their mouth, especially when new grass is emerging for the first time during the spring, or when the dog is thirsty.

Is eating grass bad for dogs?

The AKC says the consumption of grass may just be a sign that a dog is attempting to relieve an upset stomach, and that some dogs do vomit soon after eating it. That said, the AKC reports that a small, limited study conducted at the UC Davis School of Veterinary Medicine showed that only about 22% of dogs studied frequently vomited after eating grass, and only 9% frequently showed signs of illness prior to eating grass. The researchers concluded that grass and plant-eating is a normal behavior of domestic dogs.

The AKC also notes two cautions about the grass itself:

• Treated grass. Grass that has been treated with herbicides and pesticides can be toxic to dogs.
• Parasites. Eating grass can also cause dogs to ingest intestinal parasites, for example roundworms and hookworms, that are left from animal droppings.

When to call the vet

The AKC says that if you notice your dog eating grass more frequently or excessively, be alert for potential underlying illnesses that may be causing the behavior. The AKC says to check for:

• vomiting,
• diarrhea,
• weight loss,
• decrease in appetite,
• bloody stool,
• lethargy, or
• lip licking.

The AKC also says that frequent vomiting should be evaluated by a veterinarian, and that increased grass-eating paired with symptoms like lethargy, diarrhea, or weight loss may indicate an underlying health issue and should be checked by a veterinarian. In its key takeaways, the AKC puts it this way: persistent or symptomatic grass-eating should be evaluated by a veterinarian.