Glycyrrhizin concentrations ≥100 μg/ml inhibited H5N1 A/Thailand/1(Kan-1)/04 (MOI 0.01)-induced activation of the initiator caspases 8 and 9 as well as of the effector caspases 3/7 in A549 cells as determined 24 h post infection (Figure 4A–C). This evidence concerns the gene CASP8 and infection.