Objective: To explore the therapeutic mechanism of the combined use of Radix Salviae Miltiorrhizae, ligustrazine and Radix Sanchi in treating late hemorrhagic shock in rabbit. Methods: Rabbit hemorrhagic shock models were set up according to Wiggers’ method and treated with the combined therapy. Levels of RBC superoxide dismutase (SOD) activity, plasma malondialdehyde (MDA), blood lactate (BL) and magnesium (Mg++ ) were continuously monitored before shock, 120 minutes after shock, 60 and 120 minutes after reinfusion. Results: (1) Levels of SOD decreased and MDA, AL, Mg++ increased markedly 120 minutes after shock, indicating that there existed cell membrane damage caused by oxygen free radicals in hemorrhagic shock.(2) The combination therapy could alleviate lipid peroxidation injury to tissue, enhance the activity of SOD and lower the concentration of MDA significantly, P < 0. 01 or 0. 05, as compared with the control group. Conclusion: The combined use of the three drugs could gain the same effect with half dosage as that gained from the whole dosage of one single drug. It could also reduce the negative effect of treatment, such as hypotension and slowing down of heart rate Objective: To explore the therapeutic mechanism of the combined use of Radix Salviae Miltiorrhizae, ligustrazine and Radix Sanchi in treating late hemorrhagic shock in rabbit. Methods: Rabbit hemorrhagic shock models were set up according to Wiggers’ method and treated with the combined therapy. Levels of RBC superoxide dismutase (SOD) activity, plasma malondialdehyde (MDA), blood lactate (BL) and magnesium SOD decreased and MDA, AL, Mg ++ increased markedly 120 minutes after shock, indicating that there existed cell membrane damage caused by oxygen free radicals in hemorrhagic shock. (2) The combination therapy could alleviate lipid peroxidation injury to tissue, enhance the activity of SOD and lower the concentration of MDA significantly, P <0.01 or 0.05, as compared with the control group. Conclusion: The combined use of the three drugs could gain t he same effect with half dosage as that gained from the whole dosage of one single drug. It could also reduce the negative effect of treatment, such as hypotension and slowing down of heart rate