One theory goes that eating and vomiting grass has evolutionary benefits. If the wild canid took a chance and ate something she shouldn’t have, it likely caused a digestive upset, and this triggered an instinct to eat even more grass than normal.
This major league chew, if you will, served two purposes. The mass of grass intertwined with the offending material and irritated the lining of her stomach, resulting in the whole shebang being heaved up faster than a supermodel after eating the buffet at Golden Corral.
Some people think all dogs tend to eat grass when they have a stomach upset, even if the cause of the nausea isn’t dietary indiscretion (emptying the contents of the cat’s litter box, the garbage can or digging up something disgusting).
While the ‘grass is always greener when it passes out the other side’ theory is sometimes true, I think that dogs eat grass — especially in the spring — because it tastes good and/or fills a nutritional need for fiber and chlorophyll, both of which aid in digestion. When I see three of my four dogs eating more grass than someone with fibromyalgia in Colorado, I know it’s not nausea but just a appetizer (or should I say crap-itizer?) for the main course.