Eating Grass

Question
Hi Jannie,

I have a 5 yr old male boxer that will stop and graze on grass, sometimes he vomits and sometimes he gets the runs. This occurs every couple of days.  
I know that dogs & (wolves) have a history that dates way back when it comes to including grass their diets. (A fresh kill's intestines would include grass)   
However, it concerns me as there wasn't a problem all winter (no grass just snow) but now that the weather is better and grass is growing he continues to eat it.
It would appear that he wants to vomit...would his stomach be upset?  Is there something lacking in his diet?
The Vet doesn't really seem to be too concerned about this but I am at a loss as to what I can do or what I can try.
My wife is not too happy about cleaning up after him nor am I.
Anything that you can suggest on what to try or correct would be greatly appreciated.
Thanks!

Answer
It sounds like his dog food diet is not adequate for him so he is supplementing his diet with cravings.

What food do you have him on?

Also, change vets. If a vet cannot get to the bottom of a problem and know, then he or she should be replaced with a vet that does.