Are the mushrooms that grow in the grass poison?

There are a bunch of wild mushrooms that grow in my front yard. Just want to know if they are poison or not.
Update: They are white, and relatively small. I wasn't thinking about eating them, was just curious if they might be poisenous. And Rawr!, and Dfdg,do everyone a favor and don't bother answering anymore questions. Jerks.
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