Hmm, this is a popular question in the veterinary world. I get asked this question numerous times (luckily in our climate it is only for about 6 months of the year!) and sometimes I just don’t know the correct answer. There are many theories as to why these guys tend to binge on the green stuff.
From an evolutionary standpoint, it may have been beneficial for dogs to remove any evidence of their sent to prevent predation. However, it our modern world it seems as though our Fido’s and Rex’s go outside and shop for the most appropriate selection of long blade grasses and indulge and are probably not concerned about their own scent.
A more common reason for grass eating is often nausea or stomach upset. Many dogs who have upset stomachs or are not feeling well will eat grass which seems to trigger them to vomit. This is certainly an important medical illness to rule out if your dog is a grass eater.
The other theory as to why your dog might be eating grass is that they may be missing something in their diet. Although grass does not have any nutritional value for dogs, it is often one of the innapropriate items that dogs who are hungry or malnourished will eat. This is definately something to rule out if your dog is on a calorie resticted diet or on a homemade diet.
The last theory on why dogs eat grass is less common but does occur. These are the dogs who eat grass as part of an obsessive compulsive disorder. This is a behavioural problem that can often be managed but sometimes needs to be treated.
Before I conclude, it is worth mentioning that I have seen on more than a few occasions, dogs who get blades of grass caught around their tonsils and up their noses and require them to be removed under sedation or anesthesia. If you have a dog who eats grass, please mention it during our visit as it may be an indication of a medical issue that needs to be resolved.