Abstract: Objective: To explore the effect of pituitrin on heart contractile in the toad.Methods: Ringers solution was used to maintain the normal action of the heart,then the heart was perfused by Ringer's solution 1 ml containing pituitrin at concentration of 0.125 u/ml,0.25 u/ml,and 0.5 u/ml,and washed before adding the next dosage.The myocardiac contractile force and heart rate were recorded separately after adding each dosage.The other part of this experiment was that the deslanoside was added to the solution when the heart failure model was caused by pituitrin (0.25 u/ml).The parameters were take down.Results: The myocardiac contractile force was reduced by adding pituitrin compared with control(P<0.05).The reduction of myocardiac contractile force was not antagonized by adding deslanoside.Conclusions: The heart failure can be caused by pituitrin and can't be antagonized by deslanoside in toad.