As far as I've read, peppermint is from the same family as catnip. But as with catnip, not all cats will react to it.
I've read conflicting information as to the safety of other peppermint products such as the plant or candies. Some recommend it to calm your cat whereas others adamantly tell you to avoid it at all costs because it's toxic. Just to be on the safe side, I just stick to known safe stuff for my cats.