Hepatic ischemia/reperfusion (I/R), characterized by severe inflammation and cell death, causes significant liver damage, and there are no effective approaches to prevent this pathological condition. We evaluated the potentially protective functions of ginsenoside Rg1 in hepatic I/R injury and the underlying mechanisms. A mouse hepatic I/R model was established by 60 min of induced ischemia followed by 0, 6, 12 or 24 h of reperfusion. Ginsenoside Rg1 (20 mg/kg/day) significantly promoted hepatic function and suppressed liver necrosis and inflammatory responses. Mechanistically, the JNK/MAPK signaling was dramatically diminished by ginsenoside Rg1. Furthermore, we unexpectedly found that only the cytotoxicity induced by inflammation, rather than oxidative stress, was significantly inhibited by ginsenoside Rg1 in vitro, and this inhibition was almost completely abolished by treatment with a specific JNK activator, anisomycin. Thus, ginsenoside Rg1 exerts protective effects against hepatic I/R in a JNK signaling-dependent manner.