This study was undertaken to determine the effects of ginseng total saponin (GTS) on stress- induced analgesia (SIA) in mice. intermittent foot shock (FS)-SIA was antagonized not by on but by naloxone in the tail flick FS-SIA which was not antagonized by naloxone in the T.F. test. On the other hand, GTS did not antagonize the continuous FS-SIA naloxone antagonized in the T.P. test. Also GTS antagonized psychological (PSIF)-SIA which was not antagonized by naloxone in the T.F. test. However, GTS did not antagonize the PSY-SIA which naloxone antagonized in the T.P. test. Forced swimming (FSIP)-SIA was not affected by both GTS and naloxone. These results suggest that the antapeonisms of intermittent FS-SIA in the T.F. test, continuous FS-SIA and PSY-SIA by GTS are mediated by non-opioid mechanisms but the antagonism of intermittent FS-SIA in the T.P. test by GTS is mediated by opioid mechanism.