While no one knows exactly why dogs eat grass, pet experts are pretty sure it's just normal canine behavior and probably nothing to worry about. If your pet seems to be nibbling on grass indiscriminately, you probably have nothing to worry about. Be careful if your dog, or more importantly, your puppy, eats a lot of grass.
However, if your dog eats a lot of grass, you may want to look at his diet. Eating enough grass provides your dog with the fiber it needs to properly digest food. The fiber in the grass can help food pass through your dog's gut more easily.
However, for other dogs, eating grass may be a way to satisfy an unmet nutritional need, or to induce themselves to vomit to relieve stomach pain. Some dogs may vomit due to the odd texture or taste of the herb, rather than any digestive issues. Vomiting may not be the main reason dogs eat grass — a small 2008 study found that only 22 percent of dogs that ate grass tended to vomit later.
Most dogs that eat grass look perfectly normal, which is why veterinarians believe grass is more likely to vomit than not. Dogs sometimes exhibit anxiety behavior before eating grass, looking for longer grasses and eating them quickly, which stimulates the gag reflex. However, less than 25% of dogs actually vomit on grass, and only 10% show signs of illness before eating grass, meaning they most likely won't eat it because they're sick.
Eating grass can be a sign that your dog is trying to relieve stomach pain, and some puppies will vomit immediately after eating it. It is normal for dogs to eat a certain amount of grass, but if your dog is showing unusual symptoms such as diarrhea or aggression, eating grass may be a sign of an underlying medical condition such as intestinal worms or anxiety.
Grass-grazing dogs are actually quite common (this has also been seen in dingoes and can be completely natural), and this form of pika is usually not a big deal. Grass consumption seems to be common among dogs and not as strange as some of the other feeding methods that puppies often do. Eating weed is considered a normal habit, inherited from wild dogs long ago. Eating grass is a habit that dogs may have inherited from wolves, which is why some puppies like to eat grass.
This grass-eating behavior may have been passed down to dogs from wolf-like ancestors. Over time, dogs became omnivores, just like us humans, which may explain why they still have an appetite for weed. Grass consumption may have evolved to help dogs hide the scent from their prey. Food is an evolutionary process, says Marty Becker, DVM, on Marty Becker's blog; ancient wild dogs felt nauseous, which caused the desire to eat grass, which irritated the stomach walls, resulting in easier grass selection and aggressive feeding.
If the dog's diet is complete and balanced, eating grass may be related to the deficiency at all, which may be an instinct. "There is some anecdotal evidence that dogs stop grazing when their owners feed them high-fiber foods," said Nicholas Dodman, BVMS, DACVB, chair of the Dog Behavior Research Center. While many believe that disease is the most likely reason for dogs eating grass, research doesn't necessarily support this theory. Some experts (like the veterinarians at VCA Hospitals) support the theory that because grass is a good source of fiber, eating it helps your dog's body function properly.
There is also some speculation that grass grazing may provide fiber or trace amounts of vitamins and minerals that are deficient in commercial dog foods. Another theory suggests that dogs crave certain nutrients found in the grass, perhaps simple micronutrients that are lacking in their normal diet. These dogs also make it clear that some dogs just enjoy eating grass regularly. It's safe to assume that some dogs just like the taste and texture of grass.
Some dogs only eat grass in certain places or at certain times of the year, suggesting that they like the taste and texture of the grass they chew. In any case, dogs tend not to chew grass as often when dog owners are outside with them. Puppies and young dogs often gnaw on grass to relieve boredom.
Once outside, your bubbly tummy may start swallowing weed. Dogs that eat until they vomit usually swallow the grass as quickly as possible, barely chewing it. Kathryn Pankratz, a certified veterinary behaviorist, says inverted dogs rarely vomit after eating grass, so dogs are unlikely to eat it to soothe their stomach pain.
In another study, researchers compared the behavior of dogs with mild gastrointestinal distress while grazing and concluded that healthy dogs were more likely to graze than dogs with upset stomachs. In another study, researchers found that young dogs were more likely to graze than older dogs, possibly because they were more susceptible to intestinal parasites.
You can try to stop eating, especially if you don't know if the grass has been treated with fertilizers or pesticides that could make your dog sick. If your pet eats grass at a dog park, look for signs that the lawn may have been treated with chemicals. As a general rule, the occasional grass-eating is not a cause for concern, but if your dog compulsively ingests foreign objects on a regular basis, you may want to check to see if he's peeking.