Currently, it is believed that the mechanism of Huang Qin (Scutellaria baicalensis) and its extract Baicalin in the treatment of psoriasis was the inhibition of the keratogenesis and cell proliferation [12], the activation of Jurkat T cells in-vitro [13] and the iNOS protein expression in fibroblast cells stimulated by cytokines, and reduce the generation of NO [14]. Here, NOS2 is linked to psoriasis.