 The investigators laboratory is studying a skin disease known as psoriasis. The purpose of this protocol is to study the action and the effects of Etanercept, on psoriasis. This medication has been studied extensively and has been found to be effective and safe in the treatment of psoriasis. The eligible patient will have 10 of hisher body surface area involved with psoriasis vulgaris. This trial is a phase III study to help understand the action of the drug etanercept, trade name Enbrel, for the adult patient with moderate to severe plaque psoriasis and who is a candidate for internal medications. 