Ginseng leaves and flowers have been known to be rich in various ginsenosides. The aim of present study is to screen the effect of 34 ginsenosides from ginseng leaves and flowers on interlukin (IL)-12 production in bone marrow-derived dendritic cells induced by lipopolysaccharide (LPS). Noticeably, floralginsenoside Kc (5), floralginsenoside J (26), and ginsenoside I (33) exhibited particularly inhibitory effect on LPS-induced IL-12 production with $IC_{50}$ values of 16.3, 25.8, and 6.7 ${mu}M$, respectively. In addition, floralginsenoside Kc (5) suppressed significantly LPS-stimulated IL-6 and tumor necrosis factor-$alpha$ (TNF-$alpha$) production. These results warrant further studies concerning potential of saponin extracts of Panax ginseng leaves and flowers for medicinal foods.