Total cardiac glycosides isolated from dry fruit of Erysium chei- ranthoides L ( ETCG ) possesed positive inotropic effect. Its effects on the physiological properties of guinea pig left atria were studied. in this paper. The effects of ETCG on dose-response curve were investigated. The results showed that ETCG increased contractility of left atria significantly and dose-dependently .The pD2 value was 7.94. ETCG ( 0.17mg/L)increased significantly excitability and automaticity induced by epinephrine. ETCG(0.01mg/L ,0 .043mg/L ,0 .17mg/L)prolonged functional refractory period obviously.