The anti-enterovirus activity of RDV was evaluated based on the human rhabdomyosarcoma（RD） cells. The half toxic concentration （CC₅₀） and half effective concentration （EC₅₀） of RDV for EV71， Coxackie virus 6（CA6）， enterovirus 68（EVD68），and Coxackie virus 16（CA16） were detected， and the selection index （SI） was calculated. The RD cells were divided into cell control group，virus control group（without treatment） and administration groups. The RD cells in virus control group were given EV71， and the RD cells in administration groups were given different concentrations （0.005， 0.015， 0.046， 0.137，0.410， 1.230，3.700，11.110，33.330，and 100.000 μmol·L^－1） of RDV. After 72 h， CellTiter-Glo^? Luminesent assay kit was used to determine the activities of RD cells in various groups. In the cell activity evaluation experiment of anti-EV71， the RD cells were divided into administration groups and virus control group.The RD cells in administration groups were given different concentrations（0.30， 0.10， 0.30， 0.80 and 2.50 μmol·L^－1） of RDV. After 30 h， the expression levels of EV71 RNA in the RD cells in various groups were detected by Real-time fluorescence quantitative PCR （RT-qPCR） method， and the expression levels of EV71 structural protein VP1 in various groups were detected by Western blotting and immunofluorescence methods. Time of addition assay was used to conform the antiviral stage of RDV.In anti-EV71 animal pharmacodynamics， 35 ICR suckling mice were randomly divided into placebo group （given 2% Tween 80， n=12），3.0 mg·kg^－1 RDV group （given 3.0 mg·kg^－1 RDV，n=12） and 1.5 mg·kg^－1 RDV ^{group （given 1.5 mg·kg－1 RDV， n=11）；each suckling mouse was challenged intraperitoneally with 5×103 PFU.The first dose was given after 4 h，and the treatment lasted for 2 weeks. The survival rates of the sucking mice in various groups were observed and recorded. On the 3rd day after challenge， the viral loads（copy number of EV71 RNA） in different tissues of the suckling mice in various groups were detected by RT-qPCR method.}

The EC₅₀ of RDV for EV71， CA6， EVD68，and CA16 were （0.05±0.01），（0.14±0.06），（0.02±0.01），and（0.10±0.03） μmol·L^－1， respectively. Compared with virus control group， the expression levels of EV71 RNA in the RD cells in 0.10， 0.30， 0.80，and 2.50 μmol·L^－1 RDV groups were decreased （P<0.05 or P<0.01）， and the expression levels of EV71 structural protein VP1 in the RD cells in 0.80 and 2.50 μmol·L^－1 RDV groups were decreased. Compared with virus control group， the copy numbers of EV71 RNA in the RD cells at stages Ⅲ and Ⅳ （virus replication stage） were decreased significantly （P<0.05）. There were no significant differences in the survival rates of the suckling mice between administration groups and placebo group （P>0.05），but there was a certain protective trend. Compared with placebo group， the viral loads in lung and muscle tissues of the suckling mice in 3.0 mg·kg^－1 RDV group were decreased significantly （P<0.05 or P<0.01）.

RDV has an excellent antiviral activity against enteroviruses （such as EV71）at the cellular level， and mainly acts on the replication stage of viral infection. RDV can significantly reduce the viral loads in lung and muscle tissues， suggesting its therapeutic potential at the animal level.