Objective:The effect of prevention and treatment of Xinkang oral liquid (心康口服液, XKOL) on experimental coxsackievirus B 3 (CVB 3) myocarditis mice model were investigated. Methods: The mice were inoculated intrap eritoneally with 0.3 ml of 10 5 TCID 50 of CVB 3 to in duce acute viral myocarditis model. These mice were divided into model control group (Group A), prevention high do sage group (Group B) and prevention low dosage grou p (Group C), treatment high dosage group (Group D) and treatm ent low dosage group (Group E), respectively. In addition, XKOL control group (Group F) and normal control grou p (Group G) were not infected with CVB 3 intraperitoneally. The administration of XKOL in Group B a nd C began 2 days before virus infection. All animals were sacrificed on day 20 for evaluation. Results: Histological examination showed extensive m yocardial necrosis and cell infiltration in most of Group A mice, but necrosis and cell infiltration were less severe in Group B,C,D and E mice. Thymus weight in Group B,C,D and E mice were heavier and less cell depletion occurred than those in Group A. Conclussion: The XKOL could effectively inhibit myoc ardial CVB 3 replication, reduce the myocardial inflammatory response, lower incidence rate of myocarditis and prevent the disease associated lymphoid organ atrophy in this animal models.