The adding effect of simvastatin Clinical effect: Simvastatin had the adding effect in the treatment of psoriasis vulgaris: 70% of patients had PASI-75; 10% of patients with Excellent PASI improvement, 60% of patients with Good PASI improvement, 10% of patients with Fair PASI improvement; và 56, 7% of pateints with IGA 0/1.