Abstract: Adonis pseudoamurensis W. T. Wang (APAW) is a new glycoside isolated from the plant Adonis L. In the present study, the inotropic and toxic effects of APAW were studied and compared with those of Adonis amurensis Regel et Radde (AAR) and strophanthin K (SK) in normal heart and experimental failing heart in anesthetized rabbits. In rabbits with normal heart, intravenous injection of APAW (1.0 mg/kg) induced an increase of p-dP/dt loop, LV-dP/dt_max, Vpm and LVSP, while the HR was slightly slowed. After intravenous infusion of APAW (0.5 mg/ml) at a constant speed for 30 min, the LV-dP/dtmax, Lo and LVSP of the failing rabbit heart induced by sodium pentobarbital significantly increased, t-dP/dtmax and LVEDP decreased, while the HR did not change. The peak inotropic effect of APAW was similar to those of AAR and SK. The therapeutic index and the safety margin of APAW were larger than those of AAR and SK. while no difference was observed between AAR and SK. These results indicate that APAW is a promising cardiac glycoside.