Objective To investigate the effect of Panax notoginsenosides monomers ginsenoside Rg 1 in inhibiting hepatic fibro-sis .Methods The rat model of hepatic fibrosis was established by using 50% Ccl4 ,total 35 d .The different doses of Rg1was ad-ministered by hypodermical injection .At the end of the treatment ,the pathological changes of hepatic tissue were observed by light and transmission electron microscope .The stereological method was adopted to measure the volume density (Vvm) ,area density (Svm) ,specific surface(Qm) and surface number density (Nam) of liver cell mitochondria in various groups .Results The stereo-logical data of liver cell mitochondria showed that the statistical differences existed among various groups .Vvm in the Panax Notog-insenosides ,low dose Rg1 and isotonic saline groups were significantly increased compared with the normal control group with sta-tistical difference(P<0 .01);Vvm in the high dose Rg1 ,middle dose Rg1 and colchicine groups showed the increasing trend com-pared with the normal control group without statistical difference (P>0 .05);Vvm in the high ,middle and low dose Rg1 ,Panax No-toginsenosides and colchicine groups showed the decreasing trend compared with the isotonic saline group without statistical differ-ence(P>0 .05) .Svm in the low dose Rg1 ,Panax Notoginsenosides ,colchicine and isotonic saline groups were significantly increased compared with the normal group with statistical difference (P<0 .01);Svm in the high dose Rg1 ,middle dose Rg1 ,Panax Notogin-senosides and colchicine groups was significantly induced compared with the isotonic saline group with statistical difference (P<0 .01);Svm in the high dose Rg1 was reduced compared with the middle dose Rg1 group(P<0 .05) .Nam in the low dose Rg1 ,col-chicine and isotonic saline group was significantly increased compared with the normal group (P<0 .01);Nam in the high dose Rg1 , middle dose Rg1 and Panax Notoginsenosides groups were significantly reduced compared with the isotonic saline group with statis-tical difference(P<0 .01);Nam in the high dose Rg1 group was reduced compared with the middle dose Rg 1 group with statistical difference (P<0 .05) .Qm in all groups was reduced compared with normal group without statistical difference (P>0 .05) .Conclu-sion Rg1 has antifibrosis effects of Panax notoginsenosides ,even exceeds Panax notoginsenosides in some aspects ,and the above-mentioned effect is positively correlated with dose .Rg1 is an ideal drug for preventing and treating liver fibrosis .