This study was performed to investigate the anxiolytic-like effects of red ginseng (RG, steamed raw ginseng at 98-100 degrees C) and sun ginseng (SG, heat-processed ginseng at higher temperature) in mice using the elevated plus-maze model. Furthermore, the anxiolytic-like effects of RG and SG were compared to a known active anxiolytic drug (diazepam). The RG butanol fraction (100 mg/kg) significantly increased the number of open arms entries and the time spent on the open arm (indicators of anxiolytic-like effects) compared with that of the saline group. However, lower doses of the SG total extract (50 mg/kg) and the SG butanol fraction (25 and 50 mg/kg) significantly increased the number of open arms entries and the time spent on the open arms. The RG total extract (100 mg/kg) and the SG total extract at a lower dose (25 mg/kg) did not increase the number of open arm entries or the time spent on the open arm. On the other hand, the RG butanol fraction (100 mg/kg), the SG total extract (50 mg/kg), and the SG butanol fraction (50 mg/kg) decreased locomotor activity in a manner similar to diazepam. These data indicate that ginseng has anxiolytic-like effects, and the anxiolytic potential of SG is stronger than that of RG in the elevated plus-maze model. Ginseng saponins have been suggested to play an important role in the anxiolytic effects of ginseng. We provide evidence that ginseng may be useful for the treatment of anxiety.