We demonstrated the anti-atopic dermatitis effects of evodiamine in a murine model, demonstrating that the effectiveness of evodiamine was caused by the inhibition of mast cell accumulation in the skin, along with the inhibition of pro-inflammatory cytokines (IL-17A, IL-4, IL-13, IFN-γ, and IL-12A) and chemokines (IL-8 and IL-6) in the lymph nodes and epidermis. The gene discussed is IL17A; the disease is atopic eczema.