Is eating grass normal or abnormal for your pet ??

I was always told that dogs eat grass when they feel sick, because it helps them to throw up and feel better. I suppose it's also possible that they eat grass because it soothes their stomach. I just know that whenever I see my dog eating a lot of grass, it most likely means that he is going to throw up soon so I try to keep him outside. I definitely don't think it's something to worry about though. Every dog I've ever owned has eaten grass at least occasionally and it hasn't seemed to affect their health.