We did some research on this subject. After speaking with vets and consulting various reputable sources on line, we came up with our own conclusions:
Theory 1: dog’s ancestors (wolves) ate grass to scour intestinal parasites.
Conclusion: household dogs given preventive meds. should not need this.
Theory 2: Grass makes up for trace minerals that may be lacking in a dogs diet.
Conclusion: some dogs may require more roughage which grass gives, so a higher fiber diet may help.
Theory 3: dogs crave more treated grass because they taste better and are found when grass is cut when walking dogs on certain laws.
Conclusion: grass is grass and some dogs eat it as a way to get attention. Just think, if you “corrected” them (and gave them attention – negative or positive) this is the ultimate reward!
Theory 4: The dog is simply hungry.
Conclusion: probably true.
If your dog is “craving” grass, why not buy a planter of cat grass. It’ll be around him all times and minimize the temptation.
Bottom line, grass eating is common in dogs and may have nothing to do with illness, or a signal to change their diet.