Objective:To explore the antagonistic effect of Fengzhecao extract against human red blood cell (RBC) hemolysis induced by wasp venom.Methods:Water extract method was used to extract dried Fengzhecao and vacuum-dried to obtain Fengzhecao extract. It was diluted into 1 g/L for next use. Wasp venom was collected from the wasp workers. A, B, O, AB type healthy blood donors' suspended RBC solution was obtain to make washed RBC solutions and adjust the RBCs count (4.0-80.0)×10 9/L (the number of RBC counted on the hemocytometer is 1-20 cells/small checker). According to treatment factors, they were divided into the normal saline controlled group (NS group; 200 μL RBC solution+20 μL normal saline), Fengzhecao extract group (FZC group; 200 μL RBC solution+10 μL Fengzhecao extract+10 μL normal saline), wasp venom group (FD group; 200 μL RBC solution+10 μL wasp venom+10 μL normal saline), and Fengzhecao extract+wasp venom group (FCD group; 200 μL RBC solution+10 μL Fengzhecao extract+10 μL wasp venom), with 10 blood samples per group of every blood type. The solutions were put into the glass test tube respectively, and then into 37 ℃ water bath thermostat. After 10 minutes, the blood cell counting plate was directly observed under the microscope and the RBCs was counted. Differences in RBC count was compared between the same treatment factors of different blood types and between different treatment factor groups of the same blood type. Results:There was no statistically significant difference in RBC count between blood types under the same treatment factors. The RBC count (×10 9/L) of the type A, B, O, AB in the NS group were 5.567±1.368, 5.146±1.690, 4.577±0.774, 5.197±1.587 ( F = 0.852, P = 0.475), the FZC group were 5.751±1.489, 5.268±1.418, 4.727±1.174, 5.298±1.229 ( F = 0.987, P = 0.410), the FD group were 0.546±0.450, 0.804±0.428, 0.679±0.283, 0.846±0.453 ( F = 1.089, P = 0.366), and the FCD group were 5.532±1.330, 5.051±1.596, 4.589±0.879, 5.140±1.492 ( F = 0.820, P = 0.492), respectively. Comparison of RBC count between groups with different treatment factors of the same blood type was done. There was no significant difference between the FZC group and the NS group, indicating that the extract of Fengzhecao extract had no effect on hemolysis of RBC; in the FD group, it was significantly lower than the NS group (all P < 0.05), indicating that wasp venom had a significant hemolytic effect on RBC; but there was no statistically significant difference in RBC count between the FCD group and the NS group, indicating that the Fengzhecao extract antagonizes the hemolytic effect of wasp venom without affecting the RBC count; however, the RBC count in the FCD group was significantly higher than that in the FD group (all P < 0.05), further indicating that the Fengzhecao extract antagonizes the hemolytic effect of wasp venom. Conclusion:Wasp venom has a significant hemolytic effect which can be effectively antagonized by Fengzhecao extract and has nothing to do with the human ABO blood type.