Treatment with EGCG attenuated skin inflammation, accompanied by reduced infiltrations of T cells; reduced percentages of CD11c+ DC in the composition of immunocytes of spleens; reduced levels of interleukin (IL)-17A, IL-17F, IL-22, IL-23 and malondialdehyde (MDA) in plasma; increased percentages of CD4+ T cells in the composition of immunocytes of spleens; and increased bioactivities of superoxide dismutase (SOD) and catalase (CAT) in plasma. Here, IL17A is linked to dermatitis.