June 14, 2025, 10:41 am | Read time: 5 minutes
Many dogs occasionally nibble on blades of grass—while some do so leisurely, others seem to frantically devour entire clumps. What drives this behavior? And when should dog owners be concerned? PETBOOK explains why dogs eat grass and when this behavior becomes problematic.
Many pet owners worry when their dog eats grass. However, almost all dogs occasionally exhibit this behavior. The key factors in grass eating are the amount and frequency. If the dog also vomits after eating grass, owners should pay attention. Causes and risks vary, but one thing can be ruled out according to a study: There is no scientific evidence linking grass eating to potential malnutrition in dogs. Nevertheless, this rumor persists among many dog owners.
Overview
What causes can grass eating have?
Nutrient deficiency has already been ruled out by studies. However, there are also explanations that are not scientifically proven. These include the theory that wolves always ate their prey with the plant-based stomach contents, and dogs therefore have an evolutionary craving for it. Other possible causes can be: 1 2
Thirst
If no water is available to the dog on hot days, it tries to quench its thirst with a few juicy blades of grass. Therefore, you should always carry a bottle of tap water and a portable bowl on walks or hikes.
Nausea and digestive problems
Dogs eat all sorts of things unnoticed when we are out with them. They might ingest something spoiled or toxic, making them feel sick. Dogs then instinctively consume a lot of grass to induce vomiting. The dog might also have swallowed a foreign object it wants to expel. Or it may have swallowed too much hair during grooming or eating, especially during shedding. Another possibility is that it played too much on an empty stomach, causing stomach acid issues. This acid is also high when the stomach is empty, which could explain why the dog eats more grass in the morning before its first meal.
Understimulation and boredom
If a dog receives too little attention and is not physically and mentally challenged, it starts to entertain itself. Some dogs begin to chew on chair legs or cables, while others discover grass eating.
Stress
If the dog is stressed, chewing helps reduce stress because chewing releases endorphins. At the same time, its blood sugar increases due to the sugars or fructans in grass, making it feel better, similar to a person reaching for a chocolate bar when experiencing low blood sugar.
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Age and health as influencing factors
The reason dogs eat grass can also depend on their age and overall health condition.
- Puppies are more prone to exploratory behavior, including eating grass, which may be less concerning as long as no symptoms of illness appear.
- Puppies that suddenly start eating more grass might be indicating an underlying health change. In this case, a veterinary examination is particularly advisable.
In general, if there is a sudden change in behavior–such as the dog eating more than usual from one day to the next–it could be a sign of a health problem.
When does it become dangerous if the dog eats grass?
If you notice that the dog frequently vomits after eating grass, you should see a veterinarian. Even if the dog drools excessively or wheezes afterward, a blade of grass may be stuck in its throat, causing irritation in the esophagus. In the worst case, the blade may need to be removed by a veterinarian under anesthesia.
When eating grass, the dog can become infected with worms and parasites because they lay their eggs there, and the dog swallows them or the larvae with the grass. Once in the dog’s intestines, lungworms, for example, can migrate further, causing symptoms like coughing, fever, breathing difficulties, nosebleeds, and physical weakness. Diseases from other animals, such as parvovirus or distemper, can also be transmitted through grass contaminated with feces.
Not dangerous, but unpleasant, is when undigested grass gets stuck in the anus. You can carefully remove it with a tissue. Be careful not to injure the anal area.
Should you let dogs eat grass?
There’s nothing wrong with a small snack now and then. If the dog wants to eat grass, make sure it’s in a forest where the grass hasn’t been sprayed with fertilizers and insecticides, which can lead to poisoning.
Also, ensure the dog only swallows grass blades and not entire ears. The awns can cause severe internal injuries. You can read more about this in this PETBOOK article.