Is eating grass normal or abnormal for your pet ??

I agree with some comments in this thread that when a dog eats grass it is a sign of unwell. My grandmother said that in the province where dogs are on the loose in the yard, they normally see them eating grass. And that's only when the dog has a tummy ache. The grass will activate the acid in their stomach that in a short while would cause the dog to vomit. And after releasing the acid, the dog is back to normal, no more tummy ache.