Objective:To analyze the relationship between toxicity and cardiotonic effect of aconitine

calculating the therapeutic index (TI) of aconitine. Method:Regarding rat's electrocardiogram (ECG) change as the index

the toxicity to heart induced by aconitine was studied. Nimodipine

one of Ca2+ antagonist

was used to make heart failure model in rats. The aconitine was injected through femoral vein continuously. The effect on heart rate

+dp/dtmax

LVDP-rate pressure product(RPP) was observed. Result:Regarding RPP or +dp/dtmax as the index of ED50 and regarding PVC or CA as the index of TD50 or LD50

LD50/ED50 or TD50/ED50 was used to calculate the therapeutic index (TI) of aconitine

TI(RPP)were 1.84

17.22 and TI(+dp/dtmax)were 1.23

11.54 respectively. Conclution:Aconitine has cardiotonic effect but has toxicity to heart. TI is small.