Contact hypersensitivity (CHS) serves as a good model of cell-mediated reaction. Epidermal langerhans cell (LC) are thought to playa crucial role in the regulation of immune reaction of the skin, which elicit the CHS response by presenting Antigen to trafficking Ag-specific T cells within the skin. However, contact hypersensitivity is regarded as a negative side of immunities, caused by increased damaging immune response. Therefore, the study of effector molecule causing immune suppression is thought to be meaningful in the skin immune response. For this aim, this study investigated the influence of pedunculagin on cytokine, IL-$eta$ expression from langerhans cell (LC). In vitro and in vivo, pedunculagin up-regulated the expression of IL-1$eta$ mRNA. After PMA stimulation in vitro and DNFB sensitization in vivo, the expression of IL-1$eta$ mRNA was down-regulated. This results suggested that pedunculagin could be immuno-modulator in skin immune system by modulating IL-1$eta$ expression.