Objective To evaluate the therapeutic effect of acitretin by systematic review of the randomized or quasi-randomized controlled trials in treating psoriasis.Methods This systematic review use Evidence-Based Medicine.Criteria for considering studies for this review are the randomized or quasi-randomized controlled trials of acitretin in patients with psoriasis from Medline,Pubmed(1996-2004),Ovid,the Cochrane library2004.4th,CBMdsic,Vip,mlpla,NSTL and some Chinese journals.Methodolgical quality assessment and...