OBJECTIVE To observe the effects of Gu Fu Sheng Capsule ([symbol: see text] GFSC) on nitric oxide (NO) level and fibrinolytic activity in rabbits with glucocorticoid-induced ischemic necrosis of femoral head (GINFH) so as to explain the therapeutic mechanism of GFSC. METHODS 48 rabbits were randomly divided into 4 groups: GFSC group A, Ma Shi Gu Pian ([symbol: see text] MSGP) group B, model group C, and control group D. The models of GINFH were produced by injection of glucocorticoid hormone for 8 weeks. From the 9th week, GFSC decoction was given to the rabbits of the group A (45 g x kg(-1) x d(-1)) and MSGP extract was given to the group B (0.17 g kg(-1) x d(-1)) and the same volume of normal saline to group C and D by intragastric infusion. The content of plasma nitric oxide (NO), and activities of tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor (PAI) were detected after the hormone was injected for 4 and 8 weeks and after the drugs were given for 4 weeks. RESULTS Compared with the group D, the contents of NO and t-PA activity in the group C decreased significantly (P<0.01), but the activity of PAI increased significantly (P<0.01). Compared with the group C, the contents of NO and t-PA activity in the group A and B increased significantly (P<0.05), but the activity of PAI decreased significantly (P<0.05), with no significant difference between the two treatment groups (P>0.05). CONCLUSION GFSC could increase the level of NO, protect endotheolial cells and improve fibrinolytic activity, which might be the mechanism of GFSC in curing GINFH.