Serum lipid abnormalities in patients with psoriasis and the adding effect of simvastatin in the treatment of psoriasis vularis” with objectives as following: To evaluate some associated factors and clinical features of psoriasis in HCMC Hospital of Dermato-Venereology. To determine the prevelance of dyslipidaemia and associated factors in patients with psoriasis. To evaluate the adding effect of simvastatin in the treatment of psoriasis vulgaris. | In our study, the treatment s were chosen because they have proven effective and familiar with physicians in routine clinical practice. Both topical corticosteroids and calcipotriol have been approved by FDA (USA) and are the first lines for the treatment of plaque type psoriasis. An important advantage of the vitamin D analogues is their potential to function in a corticosteroid-sparing fashion. This observation has led to the development of a single-agent combination product for the treatment of patients with psoriasis. In a lot of short-term and long-term clinical trials, this combination product has showed effective and safe in the treatment of mild to severe psoriasis. In clinical practice, dermatologists prefer this combination product to monotherapy (either corticosteroids or calcipotriol). Simvastatin has the moderate anti-inflammatory activity among statins (cerivastatin > atorvastatin > simvastatin > pravastatin > lovastatin > fluvastatin). It has low cost, and is commonly used, familiar with physicians.