If you mean the mushrooms then no they are not illegal when fresh, only when dried are they illegal.
Lol dried versions taste nice though O.O" I like it in my soup xD (In belgium they are legal so once in awhile my older sister buys them for me for in the soup :3)
No when put in food it won't have any effect! atleast i don't think so xD It just adds a nicer flavor :P