My brother gave me a container of chocolate-flavored wheatgrass powder (to add to smoothies, etc) last year. He swears by the stuff although he has no chronic illnesses. I went through the entire container but didn't notice any difference in symptoms or how I felt. I will say, even with the chocolate flavoring, that stuff tastes pretty awful.
So because of the taste and the fact that I didn't notice a difference, I probably wouldn't be apt to try wheatgrass again. Your experience may be different, but I don't think it'll hurt anything to try it.