Steaming Vietnamese ginseng at 120°C changed its saponin constituents and biological activities remarkably. This study was carried out to investigate changes in free radical scavenging activity and HepG2 cells viability of Vietnamese ginseng as a result of heat-processing. Powdered Vietnamese ginseng (VG) was steamed for various durations at 120°C and their methanol extracts were subjected to TLC, analysis of HepG2 cells viability by MTT assay, measurement of MRP levels and DPPH radical scavenging activity. There are at least four new spots of MeOH extracts compared with those of non-processed VG in TLC plates with increasing density under lengthening steaming duration. The antiproliferative activity against HepG2 cells of dried powdered VG was increased at 12 h steaming compared with the others while the HepG2 cells proliferative activity was highest at 48 h. However, the DPPH radical scavenging activity and the MRP levels were highest at 94 h steaming. The results from this study encourage the pharmacological study on hepatoprotective effect and chemical analysis of the 120°c processed VG.