The protective effect of Astragalus saponins or Astragalus mongholicus bunge on the micro -model of cultured new born rat heart cells infected with Coxsackie B, virus was observed. After inoculation with 1000 TCID Coxsackie B, virus, the cardiac enzyme lactic acid dehydrogenase (LDH) was much lower in the Astragalus saponins or Astragalus mongholiais bunge treated groups than in those untreated groups, but the synthesis rate of DNA was higher. Virus titer in the supernatant of cultures was detected 48 h after virus challenge. The virus titer of the Astragalus saponins (Lg 3.78 TCID) or the Astragalus mongholiais bunge (Lg 4.33 TCID50) treated groups was lower than in those untreated groups (Lg 5.78 TCID50). These results show that the Astragalus saponins may be a useful drug in treatment of acute viral myocarditis.