Pharmacogenomics Study on Treatment of Psoriasis Vulgaris by Acitretin Capsules

Inclusion Criteria: 1. Diagnosed according to Classification criteria for Psoriasis vulgaris 2. Patients aged 18 to 70 years (to the date of screening) 3. PASI grade ≥7point 4. Not treatment in the Topical corticosteroids, Immunosuppression, Biologicals agents or Tretinoin cream, Phototherapy nearly one months before enrolled. 5. Total bilirubin \< 1.5 x ULN, AST(SGOT)/ALT(SGPT) \<2.5 x ULN if not liver metastases\<5 x ULN if known liver metastases, Creatinine clearance \<1.5 x ULN 6. Understanding the whole process of the study, voluntary participation and signed the informed consent Exclusion Criteria: 1. Pregnant women, ready to pregnant or lactating women 2. Have a serious heart, lung, kidney and other vital organs and endocrine system lesions and the history 3. Patients is liver function abnormal persons (ALT above the center laboratory normal limit) or hepatitis b patient grain carriers 4. Patients with chronic diarrhea, or peptic ulcer nearly 1 year 5. Patients suffering from malignant tumor 6. Patients suffering from acute and chronic infectious diseases 7. Mental disorders, history of alcohol abuse, drug or other substance abuse 8. Other cases which researchers believe that can not enroll