Ask Dr. Jenn: Why is my dog eating grass?

I know how frustrating that can be, especially when you are trying to get your puppy to focus on the important task at hand: emptying his bladder. Some dogs will eat so much grass they have no room for food in their stomach. They may throw up or simply not want to eat.  This leads to the common misconception as to why dogs eat grass – most people think dogs eat grass to make themselves vomit. But in most cases, it is the opposite – they get an upset tummy because they ate so much grass.

Other theories as to why dogs eat grass include dietary deficiencies, intestinal parasites, stomach pain, boredom, or stress. However, studies have shown there is no link between eating grass and gastrointestinal disease or dietary deficiencies. In the majority of cases, dogs eat grass simply because they like the taste.

Although the problem is most likely behavioral, it is important to look for reasons why your puppy wants to fill up on grass. Are you feeding him enough calories in a day? Dogs under one year of age should be eating high-quality puppy food. Most dog food bags have feeding guides to tell you how much to feed based on your puppy’s age and weight. If you can’t find this information, your veterinarian can help you calculate your puppy’s caloric needs. Are you feeding him often enough? If he is getting enough food but only eating once daily, he may be hungry later in the day and be filling his empty tummy with grass.

Bring a stool sample to your veterinarian to look for intestinal parasites. Although worms do not cause grass-eating, they interfere with the absorption of nutrients from the gastrointestinal tract, causing weight loss, protein loss, and anemia.

If your puppy is eating well, gaining weight, and doesn’t have intestinal parasites, unfortunately, he just likes the taste of grass. To help prevent the behavior, take him outside on a leash. Teach him the command “leave it” and reward him with treats and praise when he listens. If the praise and treats aren’t enough incentive, you may need to find an area with no grass, dandelions, leaves, or other plants to walk him until he urinates. Then take him back to the grassy area and play with him. Throw the ball or play chase to distract him from eating the grass.

Most dogs eventually outgrow grass-eating behavior. If your dog is one of the few that don’t, the good news is that a little grass is unlikely to harm him. Check your yard to make sure there are no toxic plants he could potentially eat, such as the Sago Palm, lilies, rhubarb, or Oleander. Make sure the grass is free of chemicals. Keep your grass short and clean up any clumps of grass left by the lawn mower. When you get frustrated, remember, at least he isn’t eating your socks.