Red ginseng and fermented red ginseng were prepared, and their composition of ginsenosides and antiischemic effect were investigated. When ginseng was steamed at 98-$100{circ}C$ for 4h and dried for 5h at $60{circ}C$, and extracted with alcohol, its main components were ginsenoside $Rg_3$ > ginsenoside $Rg_1$> ginsenoside $Rg_2$. When the ginseng was suspended in water and fermented for 5 days by previously cultured Bifidobacterium H-1 and freeze-dried (fermented red ginseng), its main components were compound K > ginsenoside $Rg_3{geq}$ ginsenoside $Rg_2$. Orally administered red ginseng extract did not protect ischemia-reperfusion brain injury. However, fermented red ginseng significantly protected ischemica-reperfusion brain injury. These results suggest that ginsenoside Rh2 and compound K, which was found to be at a higher content in fermented red ginseng than red ginseng, may improve ischemic brain injury.