In order to investigate the immunomodulational effects of Lonicerae Caulis et Folium, the author measured cytokines production(IL-10, IL-12(P35), IL12(P40), $IFN-{gamma}$) in mice splenocytes. The results were obtained as follows : 1. The water extract of Lonicerae Caulis et Folium significantly enhanced the gene expression of IL-12(P35), IL-12(P40), but reduced the gene expression of IL-10, $IFN-{gamma}$. 2. In water fraction and ethyl acetate fraction, the gene expression of IL-12(P35), $IFN-{gamma}$ was significantly increased and that of IL-12(P40), IL-10 was decreased. The above results demonstrate that Lonicerae Caulis et Folium has enhancing immune activity by upregulation of these cytokines. Therefore, if we make the relationship between these cytokines(IL-10, IL-12, $IFN-{gamma}$) besides IL-1, IL-4, IL-6, $TNF-{alpha}$, IL-8, $TGF-{eta}$ and so on which concerned the immunopotentiation, the immunopotentiational mechanism of Lonicerae Caulis et Folium will be shown clearly.