The study is to investigate the effect of Yixin Jiedu Granule on animal arrhythmia induced by CaCl₂ and Aconitine.Methods:Sixty minutes later of the last medication, rats were injected sublingually with the CaCl₂ or Aconitine, and assessed for any change or arrhythmia on ECG.Results:Yinxin Jiedu Granule at the dosage of 3g/kg significantly raised the survival rate of rats of arrhythmia induced by CaCl₂; at the dosage of 1.5-6.0g/kg it postponed the occurrence of arrhythmia induced by Aconitine, and shortened the duration of arrhythmia.Conclusion:Yixin Jiedu Granule has significant protective effect on arrhythmia of lab animals.