Objective To observe the therapeutic effect of Modified Qili Powder（Modified Seven Pinches Powder）in preventing postoperative deep vein thrombosis（DVT）after hip or knee replacement.Methods Forty patients after hip or knee replacement were randomized into the treatment group and control group

with 20in each.The treatment group was given 3g Modified Qili Powder twice daily from 1day before operation to 6days after operation.The control group was given subcutaneous injection of low molecular weight heparin 0.4ml daily.Both groups were treated for 7days.The blood rheology index and platelet count were detected 1day before operation and on the 2nd

4th and 6th day after operation.The wound drainage

adverse reactions and DVT were observed on the 3rd day after operation.Results Comparing with one day before operation

the blood rheology index and platelet count were significantly different on the 2nd

4th and 6th day after operation in both groups（P<0.05）.There was no significant difference between groups in the blood rheology index and platelet count on the2nd

4th and 6th day after operation（P>0.05）.Comparing with the control group

the total volume of wound drainage in 3days after operation was significantly lower in the treatment group（P<0.05）.There were 7cases of adverse reactions in the control group and 1case in the treatment group

with a significant difference between groups（P<0.05）.There was no significant difference between groups in the incidence of DVT（P>0.05）.Conclusion Modified Qili Powder can effectively prevent DVT after hip or knee replacement with a better effect in reducing the wound drainage and adverse reaction as compared with low molecular weight heparin.