Abstract: 　Objective] To study the synergistic action of a combination of guanghuoxiang volatile oil (B) and sodium artesunate (SA) against Plasmodium berghei (P.b) and the resistance-reversal activity against SA-resistant P.b (P.b SA-R). [Methods] Mice infected with P.b N or P.b R were treated with a combination of B and SA respectively by 4-day suppressive test method and linear regression to calculate the SD₅₀ of B and SA for each drug alone and in combination (equally effective dose compatiblity). [Results] B alone, N:SD₅₀=87.64±19.58(GKD),R:SD₅₀=43.24±7.71(GKD); SA alone, N:SD₅₀=0.88±0.01(MGKD), R:SD₅₀=27.69±0.93(MGKD). B and SA combination, N:B SD₅₀=36.89±4.57(GKD), SA SD₅₀=0.39±0.05(MGKD); R:B SD₅₀=7.40±1.30(GKD),SA SD₅₀=4.21±0.74(MGKD). The synergistic indexes of B and SA in combination were 2.2 for N and 6.6 for R, respectivly. The multiple of resistance reversal of B vs SA was 6.6. The relative reversal rate was 87.6%. [Conclusion] A combination of B and SA may enhance the antimalarial effect against P.b and reverse the SA-resistance of P.b and delay the occurrence of resistance to SA in N.\;

Key words: Guanghuoxiang volatile oil, sodium artesunate, drug combination, Plasmodium berghel, synergistic action, resistance reversal.