to observe the protective effect of Yixin Jiedu Granule on arrhythmia in lab animals induced by CaCl₂ and aconitine.Methods:60 minutes after last medication，CaCl₂ and aconitine were sublingually injected to induce arrhythmia in rats whose conditions were measured by ECG.Results:The survival rate of rats intervened by CaCl₂ was significantly improved at the dosage of 3g/kg; with a dosage of 1.5~6.0g/kg，onset of arrhythmia was delayed and duration shortened.Conclusion:Yixin Jiedu Granule has a remarkable protective effect on arrhythmia in lab animals.