Purpose. To clarify the role of perforin-and Fas ligand （L）-mediated cytotoxicity pathogenesis of viral myocarditis. Materials and methods. Forty balb/c mice were randomly divided into experimental group （n = 20） and control group （n = 20）

and inoculated intraperitoneally with coxsackievirus B3（CVB3） and Eagle’s solu- tion without CVB3

respectively. The mice were sacrificed and their hearts were removed at day 7 post-in- oculation. Expression of perform and FasL were detected with immunohistochemistry

reverse transcription-polymerase chain reaction （RT-PCR） and in situ hybridization. Results. （1）Perform-and FasL-positiye cells were demonstrated in experimental murine hearts by im- munohistochemistry

however

no cells were discovered in control murine hearts; （2） The examination of RT-PCR showed the positive ratios of perform and FasL mRNA in myocardium were significantly higher in experimental group （100% and 100 % ） than that in control group （20% and 30 %

P<0.05）; （3）Positive signals of perform and FasL mRNA were found in myocardium of all the experimental mice by in situ hybridization

but nothing was detected in control group. Conclusion. Perform and FasL can be expressed in infiltrating cells in murine myocardium with acute myocarditis caused by CVB3

suggesting perform and FasL might play an important role in pathogenesis of viral myocarditis.