Because the T lymphocytes (especially Th17 cells) play an important role in the pathogenesis of psoriasis, our results demonstrated that BAC could reduce the infiltration of Th17 cells and reduce the serum level of IL-6, TNF-α, IL-23 and IL-17 in IMQ-induced mice, indicating that BAC could suppress inflammation on both cutaneous and systemic level. This evidence concerns the gene IL17A and psoriasis.